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Yearbook 2018
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Welcome Space is many things: cold, dark, inhospitable, unimaginably vast and almost a perfect vacuum. But it’s not empty. Stare up at the sky after the Sun has gone down and the dark canvas that surrounds us is perforated by countless pinpricks of light. These tiny specks are the planets, stars, nebulae, comets, constellations and galaxies that occupy the nothingness and light the night sky up with fascination. The sight of these objects hanging in the sky is impressive enough when seen with just your eyes. But bring a pair of binoculars or a telescope into the equation and you open a window onto another world filled with marvels and curiosities. And the deeper you’re able to look, the greater the insight into these many and varied objects you’ll get. What complicates matters, however, is the unavoidable fact that our planet, the platform from which we view the heavens, is always moving, meaning the portion of the sky that’s visible to us changes with every passing day. So in order to witness the full array of spectacles the night sky has to offer, you need to know not only where but
also when to look for them. And that’s where this 2018 Yearbook comes in. Over the following pages you’ll find all the information you need to locate and observe the finest sights the night skies have to offer over the coming 12 months. There are also tips and advice on the best equipment to use and devices that can provide better, safer or alternative viewing experiences – some of which you can make yourself. With this Yearbook you’ll have all you need to know about the best astronomical sights to look out for and look forward to in 2018. Enjoy!
Chris Bramley Editor
EDITORIAL
BBC WORLDWIDE
Editor Chris Bramley Art Editor Steve Marsh Production Editor Rob Banino
President of UK and ANZ Marcus Arthur Director of Consumer Products and Publishing Andrew Moultrie Director of Editorial Governance Nicholas Brett Publishing Director, UK Publishing Chris Kerwin Publisher Magazines and NPD Mandy Thwaites UK Publishing Coordinator Eva Abramik (uk.publishing@bbc.com)
CONTRIBUTORS Jamie Carter, Will Gater, Tim Jardine, Peter Jenkins, Pete Lawrence, Martin Lewis, Michael Moltenbrey, Paul Money, Garry Palmer, Mark Parrish, Steve Richards, Neil Wyatt
CIRCULATION / ADVERTISING Head of Circulation Rob Brock Advertising Managers Neil Lloyd (0117 300 8276) Tony Robinson (0117 314 8811)
PRODUCTION Production Director Sarah Powell Production Coordinator Derrick Andrews Reprographics Tony Hunt and Chris Sutch
PUBLISHING ISTOCK
“The deeper you’re able to look, the greater the insight into these many and varied objects you’ll get”
Publisher Jemima Dixon Managing Director Andy Marshall CEO Tom Bureau
www.bbcworldwide.com/uk--anz/ ukpublishing.aspx © Immediate Media Company Bristol 2017. All rights reserved. No part of Yearbook 2018 may be reproduced in any form or by any means either wholly or in part, without prior written permission of the publisher. Not to be resold, lent, hired out or otherwise disposed of by way of trade at more than the recommended retail price or in mutilated condition. Printed in the UK by William Gibbons Ltd. The publisher, editor and authors accept no responsibility in respect of any products, goods or services which may be advertised or referred to in this issue or for any errors, omissions, misstatements or mistakes in any such advertisements or references.
Like what you’ve read? Email us at: contactus@ skyatnightmagazine.com
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Yearbook 2018
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Stargazing with a smartphone 2018
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STARGAZING with a
SMARTPHONE
Thanks to smartphone apps, you can now keep a wealth of astronomical knowledge in your pocket. Jamie Carter reviews some of the best available right now our smartphone can be a powerful accessory during an observing session. By combining GPS positioning and an accelerometer, your phone can tell not only where you are on the planet, but exactly where you’re pointing it; cue planetarium apps that show you exactly what you’re looking at in the night sky. There are apps to help you plan observing sessions, find satellites and the International Space Station. There are apps that aid astrophotography, and provide the latest astronomical updates. Over the page, we look at 15 of these essential tools for astronomy. >
ISTOCK
Y
ABOUT THE WRITER Eclipse-chaser and dark skies expert Jamie Carter is the author of A Stargazing Program for Beginners: A Pocket Field Guide.
With the right apps your phone can be used to track satellites, identify mystery stars and even as a direct feed into NASA
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WorldMags.net Observing aids GoSkyWatch Planetarium Price: £3.99 Platform: iOS Pros: Target-search; celestial grid design; red-light mode Cons: Bright stars only; obvious and invisible planets are treated the same
Stellarium Mobile Sky Map Price: £2.99/£2.19/£1.49 Platform: iOS/Android/Windows Phone Pros: Realistic views; red-light mode; light-pollution slider Cons: Mostly technical data on stars This planetarium app from the creators of the original and free Stellarium computer software impresses by keeping it real. As well as a virtual horizon, it has an option to mimic what you can see with the naked eye, and even a light-pollution adjuster. Overlays of the constellation lines, and equatorial and azimuthal grids can be superimposed. There’s also an easy-to-reach red-light mode and an unexpected section on the star lore of other cultures, including Inuit, Navajo and Aztec. https://noctua-software.com
This app for casual stargazers treats bright stars and planets like targets against a celestial grid view that remains the same whichever orientation you hold the phone. A voice announces that you’ve found a planet. Is Pluto a planet? You decide – there’s an option to choose ‘Pluto is Planet’ in the settings. Announcing distant planets could be misleading since they’re impossible to see with all but powerful telescopes, but the app’s target search makes it a useful tool. www.gosoftworks.com
Star Walk 2 Price: £2.99/£0.99 Platform: iOS/Android Pros: Easy time travel; tablet version allows voice search; red-light mode Cons: Detailed content requires an in-app purchase
Heavens-Above Price: Free Platform: Android (iOS in development) Pros: Simple design; accurate predictions; red-light mode Cons: Only shows man-made satellites; adverts along the bottom If you want to find a man-made object in orbit, you’ve come to the right place. Anyone wanting to see the ISS, a bright satellite or witness an Iridium flare probably already knows about the excellent Heavens-Above website; this app uses the same prediction engine to make calculations specific to your GPS position. It does so in a basic but thorough manner, with a list of events visible that night, as well as a dedicated section for each type of object. www.heavens-above.com
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This beautifully designed app has a useful time travel mode: touch the clock in the top-right corner then drag a finger up the side of the screen and the night sky goes into fast-forward, at any speed you desire. That’s useful for planning long (and future) observing sessions, as is the Sky Live page, which gives at-aglance rise and set times for planets and the Moon. However, detailed information on constellations, deep-sky objects, planets and satellites will all cost you extra. www.vitotechnology. com
Stargazing with a smartphone 2018
WorldMags.net Practical aids SkySafari 5 Pro Price: £38.99 Platform: iOS/Android Pros: Remote control of Go-To telescopes; extensive data; custom observing lists; red-light mode Cons: Expensive; a huge app at 1.7GB; requires telescope accessories No app goes as deep as SkySafari 5 Pro. On its own it’s a great astronomy app: you can create observing lists, check celestial coordinates, get ISS/Iridium satellite notifications, view images from the Digitized Sky Survey and even explore an intergalactic map of where an observing target is in the Universe relative to the Sun. However, this app is both expensive and huge in terms of file size. Using it to remotely control a computerised Go-To telescope requires a separate adaptor to let the app communicate with the setup, which can cost several hundred pounds. http://skysafariastronomy.com
Universe2go
Celestron SkyPortal
Price: Free Platform: iOS/Android Pros: Free app; excellent audio narration; accurate augmented reality overlays Cons: Larger smartphones won’t fit in viewer
Price: Free Platform: iOS/Android Pros: Remote control of telescopes; audio tours in earphones Cons: Brand specific; large app at 296MB; red-light mode
Of the many planetarium apps, there are few audio guides or augmented reality offerings that overlay information directly onto the night sky. This one is both. For best results it should be used with a Universe2go star viewer (£79); insert a regularsized phone into the casing and look through the viewer to see star names and constellation boundaries overlaid onto the real night sky. Aim the virtual target at a specific object and an audio narration begins. Without the viewer you can put the app into planetarium mode on a phone or tablet and hear the same audio. http://universe2go.com
Celestron’s SkyPortal can be used to wirelessly control models from both the brand’s NextStar Evolution line-up of SchmidtCassegrain telescopes, or with any computerised Celestron telescope when used with a SkyPortal Wi-Fi module (£120). After an easy pairing and alignment process the app allows your phone to act as a wireless hand controller; tapping an object on the phone screen will make your scope centre it in the eyepiece. At its core is a great planetarium app, with four hours of audio commentary – and it’s available to download for free. www.celestron.com
Scope Nights Price: £4.99 Platform: iOS Pros: Forecasts for specific locations; dark-sky advice Cons: Forecasts not always accurate Every amateur astronomer yearns for clear, dark skies, and this exhaustive app helps you find them. It presents a simple 10-day weather forecast for your GPS location alongside a rating for all-night stargazing (poor, fair, good, etc). But it’s the ‘Scope Sites’ section that impresses most, allowing users to both save favourite observing locations and search for new ones. It even includes locations where amateur astronomers are regulars, such as observatories and officially designated dark-sky sites. Lastly, a dark-sky map allows you to see how much light pollution there is at a site. http://eggmoonstudio.com >
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WorldMags.net Astrophotography Adobe Photoshop Express Price: Free Platform: iOS/Android/ Windows Phone Pros: Effective noise reduction Cons: Fewer options than desktop version If you’re doing astrophotography or creating nightscapes using a camera with Wi-Fi, this app version of Photoshop makes a good stand-in for the desktop software so popular with astro imagers, letting you edit and check photos on the go. Key features include sharpen, clarity and exposure sliders, but most useful is a clever noise-reduction feature that automatically zooms-in on the image. It also includes shortcuts to upload finished images to everything from Adobe’s Creative Cloud to social media. www.adobe.com
PhotoPills Price: £9.99 Platform: iOS/Android Pros: Precise positioning for Sun; Moon and Milky Way Cons: Complex interface takes some getting used to Want to capture that iconic moonrise or moonset photo where our lunar companion glows orange as it hangs above the horizon? PhotoPills can help by showing you exactly where the Moon will be at dusk on the day of the full Moon, so you can plan the shot. Remarkably, it can do the same for the Milky Way, which makes PhotoPills unique. There are some great advice and tutorials on the developer’s website. www.photopills.com
NightCap Pro Price: £1.99 Platform: iOS Pros: Manual camera controls; records photos as TIFF files Cons: Limited by your phone’s camera quality Of the many apps that allow you to take images in low light conditions, NightCap Pro is the most astrophotography centred. The app gives you the manual control to take DSLR-like nighttime photographs using a phone camera; presets include stars, the ISS and meteors; there’s even a star trails mode. The ISO goes all the way up to 6,400, there’s built-in noise reduction and an intervalometer for night-sky timelapses, and it even records photos as TIFF files. All that’s needed alongside it is a phone holder, a tripod and clear skies. www.nightcapcamera.com
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Stargazing with a smartphone 2018
WorldMags.net Education Cosmic Watch Price: £4.99/£3.35 Platform: iOS/Android Pros: Creative design; encourages a new perspective on stargazing Cons: Large app at 178MB Time is not a number, it’s a precise position in space, as you’ll quickly learn from this stunning 3D app that’s both a standard world clock and an astronomical timepiece. You look onto Earth from above your actual GPS location, and see which stars and constellations are overhead. Meanwhile, the changing positions of the Sun, the Moon, the planets on their orbits and even the shifting position of the Milky Way beyond are all integrated to create an app packed with detail. http://cosmic-watch.com
NASA Price: Free Platform: iOS/Android/Kindle Fire Pros: Live rocket launches on NASA TV; latest images from NASA missions Cons: NASA’s Astronomy Picture of the Day images are scattered through the app Who can resist watching a rocket launch live? Mainstream TV channels rarely broadcast such launches, but it’s all on NASA TV, which you can watch through NASA’s app. Highlights include uninterrupted and multi-feed coverage from launch pads, views inside the ISS and a live webcam outside the space station that’s pointed towards Earth. The app also contains the very latest images from Curiosity and Spirit rovers on Mars, updates on all NASA space exploration missions and more. www.nasa.gov/nasaapp
ESA on Flickr
Space
Price: Free Platform: iOS/Android Pros: Regular updates; easy to use Cons: No dedicated app
Price: £2.99 Platform: iOS Pros: Impressive animation; illustrations and music Cons: Fact-hungry kids may get frustrated
ESA is at the heart of all spaceflight in Europe. At the time of writing the organisation was between apps, but preparing to launch ESA InTouch (http:// esaintouch. net). Meanwhile ESA continues to regularly upload to photo-streaming app Flickr, sharing the latest images from its missions around the Solar System and behind-the-scenes photos. The app is easy to navigate and photos are split into albums for each mission or theme. www.flickr.com/photos/europeanspaceagency
Want to throw rocks at Curiosity? You can with this well-thought-out space ‘playscape’ for kids, produced by some talented illustrators and animators. It gives a valuable perspective on the Solar System and its planets through simple games and close-up views. Designed for kids from four years old and up, it offers an interactive journey to the planets, their moons and the Sun, but it’s all done through show and play. There are no captions, no spoken words, just great animation and a suitably creative soundscape. https://tinybop.com/apps/space
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Fixing noise makes a monumental difference: on the right is the single best frame from a video of Jupiter, on the left the final edit
TURN DOWN THE
Are your planetary images suffering from the graininess of noise, even after stacking? Does post-processing only make it worse? Martin Lewis might just have the answers you need 12
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Turn down the noise 2018
O
WorldMags.net
ver the past 20 years digital video imaging has developed to become the leading way of recording planetary detail. The method uses a high frame rate planetary camera to capture a stream of hundreds or thousands of digital frames. The best of them are then aligned and stacked to produce a single master frame in which most of the blurring effects of our atmosphere have been averaged out. This stack is then sharpened with dedicated 1
software to draw out surface detail and produce wonderful planetary images. To make the most of this technique, each exposure needs to be brief enough that it isn’t too blurred by the constant agitation of the atmosphere. Yet the short exposure times combined with the low surface brightness of most planets means that each frame tends to look quite grainy or noisy – similar to when you take a photo indoors in poor light. Although adding many frames together reduces
2
3
this noise, the noise can return when processing is then applied to tease out the real planetary detail. Noise in the finished image is a problem as it can drown out the fine planetary detail you want to show and destroy smooth gradients in brightness and colour. Here, we’re going to look at how image noise arises in digital video imaging and what you can do to minimise it, so you can produce better-looking planetary images. 4
[1] An example of the best single frame from a video taken of Mars; a lot of noise is apparent [2] An aligned stack of the best 1,000 video frames of Mars shows that noise has been minimised and atmospheric movement averaged out [3] The aligned stack has been processed to bring out the planet’s details, but this has brought the noise out too [4] Here, several stacks have been combined in freeware program WinJUPOS and noise reduction has been applied
What causes noise in
individual
frames? We’re all pretty familiar with what noise looks like, but what actually causes it? Well, noise in images is the unwanted variation in pixel to pixel brightness, which interferes with the true brightness variation of the object in an image. For planetary imaging there are only two sources of pixel noise that generally matter: read noise and shot noise. Read noise is electrical circuit noise that’s added to the image signal from each pixel when it is read from the sensor chip. It is generally not an issue for planetary imaging, unless you’re using narrow bandpass filters or the object isn’t very bright – the latter applies to Uranus and Neptune. In these cases read noise can start to become a nuisance, especially if the camera suffers from it occurring in obvious bands or lines. Shot noise is the main source of noise in planetary imaging and arises due to the particle nature of light. Photons from an object arrive at random intervals, meaning that the number captured by a pixel during one frame fluctuates. With all the image
pixels randomly fluctuating in this way, the planet’s image looks noisy. The magnitude of the pixel shot noise during a frame is equal to the square root of the number of photons captured. A pixel signal of 100 photons has 10 photons of shot noise, whereas for a signal of 10,000 photons the shot noise is 100 photons. Although the noise has increased by 10 times, the signal has actually increased by 1,000 times. However, the signal to noise ratio – the key measure of the shot noise – is 10 times better. For each pixel, the higher the number of photons captured in each frame, the lower the shot noise is relative to the signal. You can improve the signal to noise ratio of individual frames by using a camera with a more efficient chip or by increasing the photon count per pixel. There are a number of ways to do the latter, including: X Using a larger scope. X Increasing the exposure time, which can lead to worse atmospheric smearing effects.
Þ Individual frames of Mars taken with
an 8-millisecond exposure (top) and a 2.5-millisecond exposure (bottom); note that the latter has worse shot noise
X Using a camera with larger pixels or imaging at a shorter effective focal length, both of which spread the light over fewer pixels, which can reduce resolution. Although noisy frames can make focusing more difficult, don’t worry unduly about noise in individual frames. What matters is the noise after the frames have been stacked. >
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WorldMags.net Stack your frames to
reduce shot noise
By stacking your frames you’ll reduce random noise, but this reduction depends on the size of the stack. By recording for longer you can reduce the noise in the stack. In fact, shot noise reduces by the square root of the number of frames in the stack. Thus an imaging run that gathers four times as many frames will give a stacked image with half the amount of noise.
Noise reduces as stack size increases. From left to right: noise in a single frame of Jupiter’s Great Red Spot, noise in a 10-frame stack and noise in a 100-frame stack
The square-root relationship between shot noise and both the number of photons gathered and the number of frames in the stack gives rise to a key principle of great importance in planetary imaging: the amount of shot noise in the stacked image is solely dependent on the accumulated exposure time, regardless of the noise in
1
2
3
4
[1] Best frame of a two-minute recording at 60-millisecond exposure; gain 60x, low shot noise [2] Processed stack using best 30 per cent of the 2,000 frames in the recording [3] Best frame of a two-minute recording at 15-millisecond exposure; gain 240x, high shot noise [4] Processed stack using best 30 per cent of the 8,000 frames in the recording
the individual frames. You can choose short exposures (and raise the gain to give good screen brightness to allow focusing) or longer exposures (and lower the gain), but if you gather photons for the same overall duration the noise of the resulting stack should be the same. This is because when the overall duration is the same, shorter exposures will enable you to gather more frames and the increased number of frames will compensate for the increased noise. Not having to worry so much about what exact exposure and gain settings you use has advantages. It means that on fainter subjects, like Saturn, you can set a shorter exposure than you might otherwise select and bump the gain right up, knowing that you will make up for the short exposure’s high shot noise by ending up with more
frames to stack. This method of more frames at shorter exposures and higher gain reduces atmospheric smearing, producing better images overall. It does, however, assume that your camera and computer can cope with the higher frame rate without dropping frames. Compare the shots of Saturn, above. The second image from the left was captured at low gain and long exposure, the rightmost image at high gain and short exposure, but accumulated exposure time is the same. Long exposures give less noise for a single frame. However, the noise is the same in the two identically processed stacked images. Note the improvement in detail in the rightmost image is due to the significantly shorter exposure, meaning there was less smearing due to atmospheric movement.
Reducing image noise by derotating in
WinJUPOS
ALL PHOTOS: MARTIN LEWIS
Although longer recording runs allow you to gather more frames and reduce noise that way, they can fall foul of another consideration. You can’t record for too long or fine detail will be smeared by planetary
rotation, especially on fast-rotating bodies such as Saturn (below). This smearing can be overcome using the derotate function in the freeware program WinJUPOS (www. grischa-hahn.homepage.t-online.de). This
combines processed stacks together after they have been adjusted to a common time to take out the rotation. Adding stacked images together like this reduces noise, leading to more detailed images.
Þ On the left is one of three similar images combined using the WinJUPOS derotate function; the less noisy finished image is on the right
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Turn down the noise 2018
WorldMags.net Reducing noise in
post processing Þ Adjusting the denoise setting in RegiStax’s wavelet processing function can reduce noise levels and retain detail in your astro images Once aligned and stacked, your image will appear to have little noise but also little detail. To bring out the precious finer features you need to process the image using something like the wavelets function in freeware RegiStax (www.astronomie.be/ registax). Unfortunately, this processing has the unwanted side effect of bringing out the noise. On nights of better seeing, lower amounts of processing are needed to reveal the real detail, but even here some editing to reduce noise is usually required.
An effective method to reduce the noise from wavelet processing is to use the denoise function in RegiStax. Increase the denoise value until most of the noise is suppressed without affecting real detail too much. Other methods of noise suppression can be added later and can be as simple as applying a Gaussian blur to all pixels (use a blur of between 0.5 and 1 pixels in size) in a graphics editor such as Photoshop or PaintShop Pro.
There are various specialist, stand-alone noise reduction programs such as Topaz Denoise (www.topazlabs. com/denoise) or Astra Image (www. phasespace.com.au). Photoshop and PaintShop Pro plug-ins that work by targeting noise of a particular grain size and leaving the detail can also be useful. Topaz Denoise and Astra Image also do good noise reduction plug-ins for planetary imaging, as does Google Nik (www. google.com/nikcollection/products/dfine).
Can noise
help an image? It may surprise you to know that noise sometimes serves a useful function too. Almost all planetary imaging is done using 8-bit cameras with 256 grey levels. For satisfactory wavelet processing, however, the image needs to have much finer greyscale resolution: wavelet processing works best on a 16-bit image with 65,535 grey levels. 1
Thankfully, you don’t need to resort to a slower 16-bit camera, though. Stacking programs like RegiStax and Autostakkert (www.autostakkert.com) will take many 8-bit images and create a stacked 16-bit image capable of further processing. But they can only do this if there is sufficient random noise in the signal to allow it to effectively calculate the intermediate grey
levels by an averaging process. This is where shot noise helps out. If you were to drop the gain down and increase the exposure time, the signal would be so high that there would be little shot noise, affecting your ability to optimally convert the image. ABOUT THE WRITER Martin Lewis is a keen astronomer with an in-depth knowledge of how to get the best from tricky imaging targets
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[1] Normal noise in 8-bit images leads to a 16-bit stacked image like this one after processing in RegiStax to pull out detail [2] Too little noise effectively leaves an 8-bit image after stacking, with obvious errors on processing, seen especially on the left of the picture
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WorldMags.net ASTROPHOTOGRAPHY
FROM YOUR
ARMCHAIR
Michael Moltenbrey explains how you can image the skies on the other side of the world without ever leaving the comfort of your home
A
strophotographers often dream of taking that impossible image, the one that is too faint for the light-polluted sky they live under or beyond the capability of the telescope they can afford. Many astronomers in the northern hemisphere dream of capturing the majesty of the Magellanic Clouds and other southern sky stalwarts, yet are unable to make the arduous and expensive trip to somewhere that they might be able to image them. There is a solution to these woes: remote astronomy. There are several observatories around the world that will let you control their scopes from the comfort of your own computer at home for a reasonable fee – sometimes even for free. Here we look at five such telescopes to see what each has to offer. ABOUT THE WRITER Michael Moltenbrey is a computer scientist. He has been enthused about astronomy since his childhood.
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Astrophotography from your armchair 2018
WorldMags.net The Rosette Nebula in Monoceros, taken with Slooh’s T2 scope
One of the simple 6-inch reflectors in the network
MicroObservatory The MicroObservatory Robotic Telescope Network, operated by the Harvard Smithsonian Center for Astrophysics with support from NASA, is the most simplistic service here. It relies on a network of automatic 6-inch reflectors along the east and west coasts of the US, each equipped with a CCD camera. As it’s aimed at beginners and students, it is free to use. The service does have limitations. You do not have real-time access to the telescopes, but instead schedule ‘jobs’ that are automatically distributed to the telescopes depending on capacity. You can only select from a limited list of objects, comprising planets, the Moon (if visible) and a handful of deep-sky objects. There is a limited choice of four different exposure times and whether you would like to use a filter or not. The images are available as GIFs or in their raw FITS format via a common directory on the project’s website. There is still an older ongoing project that allows you to set some more detailed parameters, but for this you have to register and propose a research project. The proposals are reviewed three times per year. PROS: Good starting point; free and easy access CONS: Limited flexibility; images are often poor quality
KEY INFO
Þ Clockwise from top left: the Orion Nebula, the Moon, the Whirlpool Galaxy and a transit of Venus
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SLOOH.COM, MICROOBSERVATORY X 5
mo-www.cfa.harvard.edu/MicroObservatory LOCATIONS: Various in the US EQUIPMENT: Five 6-inch reflectors PRICE: Free
WorldMags.net The Carina Nebula, NGC 3372
iTelescope’s Siding Spring location is home to a slew of telescopes
The majestic comet Lovejoy
ITELESCOPE.NET, JOHN EBERSOLE, ROLANDO LIGUSTRI, SLOOH X 3, SLOOH/PETER ILAS, SLOOH/DAVID MIHALIC
iTelescope Currently used by more than 10,000 astronomers, iTelescope is probably the most developed service on the list. Signing up gets you access to a number of different reflectors and refractors, ranging from 3.5 inches to 27.5 inches in aperture and with varying focal lengths. Its sites are in the US, Spain and Australia, allowing you to enjoy the wonders of both northern and southern skies. All are situated in areas with little light pollution and good seeing conditions, and 70 per cent of nights are clear. Though iTelescope is described as being ready for beginners and offers many tutorials, a basic knowledge of telescopes and astrophotography is helpful since the
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system allows you to alter almost all imaginable parameters yourself. The costs for the service are reasonable as you are only charged for the time you actually take photos, and discounts of up to 50 per cent are offered when the Moon is bright. Various membership plans are available, starting from $19.95 per month. This gives you 20 ‘points’ to buy time on telescopes, with additional points available for a dollar each. Each telescope type will cost a certain amount of points – for example the T3, a Takahashi TOA-150, will cost 100 points per hour of imaging time. Once the images are taken they are available in TIFF and FITs formats on
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iTelescope’s ftp server, or can be uploaded directly to your own cloud drive. PROS: Many different telescopes and locations; full control and flexibility CONS: Interface requires practice; prior astrophotography experience recommended
KEY INFO www.itelescope.net LOCATIONS: US (California and New Mexico), Spain, Australia (Siding Spring) EQUIPMENT: 18 telescopes; refractors and reflectors ranging from 3.5 to 27.5 inches PRICE: From $19.95; additional points cost $1/point
Astrophotography from your armchair 2018
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Slooh Slooh is based on a different concept yet again. It regularly livestreams key astronomical events being observed by its telescopes, such as meteor showers and eclipses. When you control your own scope, the feed is also relayed on the website in real-time and full colour to everyone in the community. Slooh’s main observatory is located on Mount Teide in Tenerife, its scopes ranging from a 3.3-inch refractor to a 20-inch reflector, as well as meteor cams and a dedicated solar scope. Another observatory in Chile, this one with a 14-inch reflector and a 3.5-inch refractor, provides access to the southern sky. The CCD cameras mounted on
Slooh’s domes on Mount Teide in Tenerife; inset: Slooh’s T1 halfmetre telescope
the telescopes provide high resolutions of up to 4,096 x 4,096 pixels. Both sites are known for their excellent weather conditions and seeing. As of this February, you will be able to choose from three membership options: Slooh Crew (free), Apprentice ($4.95/ month) and Astronomer ($24.95/month). You do not have to pay per use, but you may be restricted in the number of images you can take depending on the type of membership you opt for. It is also possible to schedule objects for times when you would be otherwise unavailable. The finished images are stored in your personal storage area on the website. They can be downloaded in FITs format if you
subscribe for the Astronomer membership, but Apprentice and Slooh Crew members are limited to PNGs. PROS: Reasonable prices; free membership options CONS: Limited flexibility; interface easy to use but limited configuration options
KEY INFO live.slooh.com LOCATIONS: Tenerife, Chile EQUIPMENT: 10 telescopes; a range of reflectors, refractors and a solar scope, plus all-sky cams PRICE: Slooh Crew (free), Apprentice ($4.95/month), Astronomer ($24.95/month)
The Triangulum Galaxy
The waning gibbous Moon, imaged with the Slooh T1 half-metre telescope
The Western Veil Nebula
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Astrophotography from your armchair 2018
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Schulman Telescope
LightBuckets, you are given full control over the telescope, allowing you to adjust all of the parameters yourself. Although the interface for controlling the telescope is quite detailed, booking observing time is cumbersome, as no web portal exists for this purpose. Booking enquires have to be made via email or telephone and there is no calendar to show the free slots available. This makes booking via email in particular quite laborious, in spite of the responsive customer service. There are two operating modes, real-time or scheduled observation. The former allows you to quickly influence your observation by adjusting parameters on the fly, whereas the latter is quite
convenient if you have less time. Simply schedule your observation plan and it will be queued and executed automatically as soon as possible. There’s no need for you to be in front of your computer. PROS: Good location; full control of parameters; professional observatory CONS: Making a reservation is cumbersome
KEY INFO skycenter.arizona.edu/programs/remote_ observing/real_time LOCATION: Mount Lemmon, Arizona EQUIPMENT: One telescope; 31.5-inch reflector with 5,695mm focal length PRICE: $200/hour
Þ This observatory only has one scope, but it
SCHULMAN TELESCOPE X 3, ROBERT SMITH
is a monster 31.5-inch with a 6m focal length
The Schulman Telescope is hosted by the University of Arizona in the US and is located on nearby Mount Lemmon at an elevation of 2,800m. The location provides you with a dark sky, good seeing and good weather. Between September and June, 70 per cent of the nights should be clear, something you can check via its website. The telescope has an aperture of 31.5-inch and a remarkable focal length of almost 6m. As with iTelescope and
Þ The Whirlpool Galaxy in Canes Venatici
Þ The Horsehead Nebula in Orion
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ARTISTRY the internet. Over the years the category has seen some of the most incredible deep-sky images of the competition, views that would be beyond the capability of most amateur telescopes, but that’s not the only approach you can take. 2016’s winner, Robert Smith, opted to make use of an instrument little-used by amateurs, the slitless spectrograph on the Liverpool Telescope at the Roque de los Muchachos Observatory in La Palma. This device splits incoming light into its composite colours to show the different wavelengths being emitted by each. His resulting image (pictured left) of the Cat’s Eye Nebula in Monoceros and the Ring Nebula in Lyra is not only artful, but scientifically intriguing. The world’s premier astrophotography competition, Insight Astronomy Photographer of the Year, has an award dedicated to
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images captured remotely. The Robotic Scope special prize is open to all astrophotos taken with a telescope that is operated over
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The 2018 competition opens for entries on 15 January. For more details, visit www.rmg.co.uk/astrophoto
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HIDDEN SKYSCAPES Will Gater explores the secret celestial landscapes that emerge when astronomers look at some of the night sky’s most recognisable objects in infrared light hink ‘astronomy’ and most of us will envision a black sky flecked with stars or a vast expanse in which tiny worlds and distant galaxies float in the darkness. The very notion of space as an environment, a place, evokes thoughts of a void – a landscape without light, a dark celestial realm. And, yet, this view of ours is biased; human eyes detect only a meagre strip of the broad swathe of different wavelengths that the Universe shines at. The ‘dark’ night sky is in fact ablaze, permeated, with radiation. Nowhere, perhaps, are the limits of our vision more starkly demonstrated – and so much of what evades our eyes so powerfully revealed – than when we look at the cosmos at infrared wavelengths. On the next few pages we’ll do precisely that. We’ll show you what some familiar celestial objects look like when seen in infrared light, all the while exploring what we can learn from these magnificent skyscapes hidden from our sight.
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ABOUT THE WRITER
Will Gater is an astronomy journalist and presenter. Follow him on Twitter at @willgater.
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Hidden skyscapes 2018
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NASA/ESA/N. SMITH (UNIVERSITY OF CALIFORNIA, BERKELEY) AND THE HUBBLE HERITAGE TEAM (STSCI/AURA), ESO/T. PREIBISCH
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The Carina Nebula The Carina Nebula is one of the most striking deep-sky objects in the southern sky. In the Hubble panorama that serves as the background to this page, vast gas clouds shine brightly as they are excited by the light from stars embedded within this enormous whirl of star formation. Look at the same region in infrared light (above) and you get a feel for why observing at these longer wavelengths allows astronomers to get a deeper understanding of what’s going on inside these stellar nurseries.
The infrared image was captured by ESO’s Very Large Telescope and its HAWK-I camera. It shows the nebula in ‘near-infrared’ light – on the electromagnetic spectrum that is infrared radiation just beyond the visible red light that you and I can see. “In infrared light we tend to see largely things that are cooler than you see in visible light,” explains Chris North, an astronomer based at Cardiff University working on data from the Herschel infrared space observatory. “So in visible light we’re typically seeing
things that are thousands of degrees in temperature. When you get to the infrared wavelengths you’re looking at all the stuff that’s much further away from stars and isn’t heated up as much.” It’s for this reason that the hot glowing clouds seen by Hubble are barely visible, if at all, in the infrared image. Near-infrared light can penetrate dense, dusty nebulae and so in HAWK-I’s view the dark, starforming clouds within the Hubble panorama appear much more translucent. >
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INFRARED
The Milky Way Step outside on a summer’s evening and, if you’re away from light pollution, you may be able to spot the bright central region of our Milky Way rising up over the southern horizon. If you allow your eyes to adapt to the darkness you should see that within the band of the Galaxy there are numerous dark lanes and tendrils where the glow is absent, and it looks like there aren’t any stars there. These are actually dust-rich nebulae within our Galaxy’s spiral arms that are obscuring the light from the stars beyond them. The dust grains within these clouds are good at absorbing the visible light that our eyes detect, so they appear silhouetted. The longer wavelengths of infrared light, however, are able to pass through these
grains without getting absorbed, so when astronomers image the Milky Way in the infrared they can see and study the wider celestial landscape of the Galaxy relatively unhindered by these dusty interlopers. The lower picture on the left shows such an infrared view. It was taken by ESO’s VISTA telescope and shows a patch of the Milky Way close to the spout of the Teapot asterism in Sagittarius. What’s more, very cold objects in space emit a glow in the far-infrared and so the cold dust grains within these clouds (which appear black to our eyes) actually shine strongly at those wavelengths – as we see in the extraordinary Herschel image of the Andromeda Galaxy opposite.
The Orion Nebula Cast your eyes over the finest visible light images of the Orion Nebula – the really deep, long-exposure shots captured by the world’s best astrophotographers – and
there’s one thing that always stands out: the dark clouds of dust and gas that surround the nebula. These brownish-red swirls in fact extend over great swathes
ESO/VVV SURVEY/D. MINNITI/SERGE BRUNIER, ISTOCK X 2, ESO/J. EMERSON/VISTA, ESA/HERSCHEL/SPIRE/PACS/HELGA
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of Orion. Infrared views, like the one shown below, reveal that, far from being just bland cosmic murk, many conceal the nascent glow of baby stars.
Hidden skyscapes 2018 VISIBLE
WorldMags.net INFRARED
The Andromeda Galaxy While infrared astronomy has allowed us to peer into hidden realms within the Milky Way, it can also reveal the secrets of the countless galaxies that lie far beyond the limits of our own great, stellar metropolis. Some appear as little more than faint smudges of light to even the most powerful space telescopes, yet can be studied to understand the distant (and therefore early) Universe. Others, such as our cosmic neighbour the Andromeda Galaxy, M31, are much nearer – and, typically, bigger on the sky – and so offer us a chance to examine the detailed workings of another galaxy ‘up close’. Like the Milky Way, M31 is a spiral galaxy. But that’s not the only similarity the two share. In the visible light image above left, dark dust lanes can be seen meandering through its spiral arms, similar to those that weave through the bright band of the Milky Way as seen from Earth. These are silhouetted features that only appear in visible light
because they stand out against the blazing backdrop of the stars behind them. In far-infrared light, however (as seen in the view from the Herschel Space Observatory above right), the dark dust lanes appear as glowing filaments, while the myriad stars amassed throughout the galaxy, which are much hotter, seemingly disappear. The far-infrared radiation is emitted by multitudes of tiny dust grains that swirl within the lanes themselves. Those grains are produced in two different ways says astronomer Chris North. “There’s dust formed in the outer layers of massive stars. And as the stars puff off their outer layers the molecules start sticking together and forming dust grains,” explains North. “But when you look at the amount of dust in the Universe you can’t explain how all of it got there with massive stars [alone]. There simply hasn’t been enough massive stars to puff off that much stuff. And it’s actually supernovae that seem to create more dust. These events
produce dust in the immediate remnants of the explosion.” It’s no coincidence either that the dust lanes appear in the spiral arms where many bright stars are to be found. “Those bright stars are often more massive, therefore they’re hotter, they’re younger and they die sooner. They create more dust and so you end up with this cycle,” says North. As well as highlighting the delicate beauty of the Andromeda Galaxy’s dust lanes, Herschel’s far-infrared image also shows a dusty structure that may offer a window onto the galaxy’s past. “There’s this outer ring that has a diameter of about 90,000 lightyears,” says North. “That’s thought to be a merger where M31 has swallowed another galaxy, or possibly one of its neighbours – M32 or M110 – has passed through the galaxy or very near to it and caused this kind of ripple effect (not quite a shockwave) that’s created that large dust ring around the galaxy.” >
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WorldMags.net The Flame and Horsehead Nebulae VISIBLE
Around 4º from the magnificent Orion Nebula lies another stellar nursery that comes alive in infrared. In visible light the bright scallop-shelled shape of the Flame Nebula appears to be cradled by opaque tendrils of dust and gas, while its close neighbour, the unmistakable Horsehead Nebula, sits silhouetted against an immense veil of glowing gas. Yet seen at infrared wavelengths, the dense clouds that define this whole region in visible light appear transformed. In the sweeping near-infrared image above right
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from ESO’s VISTA telescope, a cluster of newborn stars emerges from within the Flame Nebula, no longer shrouded by the vast, dusty swirl that blocks our view in visible light. Meanwhile the hot glowing gas that provides a dramatic backdrop for the Horsehead Nebula in visible light is rendered invisible in this view, which instead picks up the radiation from relatively cooler material; the horse’s head itself even appears to melt away as VISTA’s infrared eyes penetrate its dark, dusty form. An even more remarkable
perspective emerges, however, when you look at this region at longer wavelengths of infrared light, the so-called ‘far-infrared’. “As you go to longer wavelengths you can see through [the Horsehead] more easily but also it starts to shine in its own light,” says astronomer Chris North. That’s what we are seeing in the Herschel view (inset above); the material in the Horsehead is glowing while, nearby, clumpy filaments of cold, dusty material – potentially the beginnings of new stars – shine where visible light showed only dark clouds.
The Pleiades Few open star clusters are as instantly recognisable as the Pleiades, a glittering collection of young stars in the constellation Taurus. But, as any astro imager knows,
what makes this particular cluster special are the delicate wisps of reflection nebulosity that accompany it. This is dust and gas suspended in space around the
ISTOCK X 2, ESO/J. EMERSON/VISTA, ESO/L.N. FLETCHER/DAMIAN PEACH
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cluster that is scattering the light from the stars. In the infrared, dust that’s been warmed by nearby stars shines brightly, highlighting exquisite filigree details within the nebulosity.
Hidden skyscapes 2018
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Jupiter
Glimpse Jupiter through a telescope and you should be able to catch sight of the intricate pattern of atmospheric belts and zones the planet is so well known for. We see Jupiter’s cloud tops in visible light because they are illuminated by the Sun. But the planet also glows in the infrared, due to the heat deep within its massive, gaseous bulk. “We believe it is the primordial heat left over from when Jupiter formed,” explains Leigh Fletcher of the University of Leicester, who used ESO’s Very Large Telescope to capture the infrared image of the planet below. Such infrared studies are useful for examining the various parts of Jupiter’s atmosphere, says Fletcher. “The various gases that are present within an atmosphere will absorb light at different wavelengths. They have their unique fingerprints no matter where they exist in the atmosphere,” he says. “If we use a filter that looks at a wavelength of light that allows us to probe high up in the atmosphere – say emission from a gas that’s high in the planet’s stratosphere – then we’ll be able to see what’s going on at those altitudes. Conversely, choose a gas such as hydrogen that allows you to probe deep down into the planet’s different layers and you can see deeper into the planet than you otherwise would just from visible light.” This process, of peering into Jupiter’s atmosphere in the infrared, is analogous to how astronomers use infrared observation to probe the depths of opaque dusty nebulae. And it can enable planetary scientists to study the three-dimensional composition and formation of Jovian weather systems, says Fletcher. “When you get storms or plumes or those sorts of things erupting we’re able to look at them in infrared light to figure out the vertical structure of those plumes and how they’re erupting from the deep cloud layers and then moving upwards into the higher atmosphere,” he says. In the image on the right, bright areas show where infrared light is streaming from deep in Jupiter’s atmosphere whereas the dark swathes are where condensed gases and icy particles are absorbing infrared radiation. “The bright regions we see in the infrared are the same as the sort of reddish, brownish regions that we see in visible light,” he says. “What that’s telling me is that reddish brown is the natural colour for Jupiter’s deep layers. And only when you have high-level clouds, fluffy white clouds if you like, does it start to block that infrared light from coming out.”
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BEST OF 2017 6RPH RI WKH Æ…QHVW DVWURQRPLFDO HTXLSPHQW WR SDVV WKURXJK RXU WHVWLQJ ODEV LQ WKH SDVW \HDU
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Equipment reviews • best of 2017
WorldMags.net Celestron CGX-L EQ 1100 EdgeHD Schmidt-Cassegrain An 11-inch telescope that delivers rich deep-sky views EdgeHD optical tube The optical tube is made from aluminium, feels very well constructed and has a Losmandy/CGE-style dovetail rail for mounting. Two dust-filtered vents at the base of the scope help reduce cooling times. A click-lock dew cap protects the corrector when the scope is not in use.
CGX-L mount head Focuser A manual focuser is provided that moves the mirror back and forth inside the optical tube as the knob is rotated. It is well matched for the scope and feels precise in use. There are two flexible tension clutches that can be tightened to prevent mirror/focus shift as the scope is rotated around the mount.
Computerised control A NexStar+ hand controller is your interface to the mount’s computer. A real-time clock retains date, time and site information even when the mount is powered down. In addition to the Go-To facilities offered from the hand controller, further control can be enabled by using Celestron’s new PWI software via an external Windows computer to provide high-accuracy multi-point sky modelling.
The CGX-L mount incorporates a heavyduty belt drive and 144mm-diameter worm wheels for smooth movement with minimal backlash. Internal optical sensors allow for positional resets and safety slewing cut-offs, ideal for remote operation. It has a 270mm dovetail clamp that fits both Vixen and Losmandy rails, and there are ports for power and external connections.
Tripod & accessory tray The telescope and mount head are supported by a sturdy tripod with 70mm-diameter steel-tubing legs. A substantial accessory tray keeps the legs in position and provides holes for 1.25inch and 2-inch accessories, as well as an upright stand for smartphones and tablets. The tripod can be folded shut with the tray still attached for transport.
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elestron’s CGX-L EQ 1100 EdgeHD is an 11-inch, aplanatic Schmidt-Cassegrain mounted on the company’s latest equatorial mount, the CGX-L. ‘Aplanatic’ refers to the additional internal EdgeHD optics, used to correct spherical aberrations inherent in this telescope design. The result is an instrument that delivers a sharp, flat field across a large area that’s good for both Solar System and deep-sky targets. A 23mm wide-angle, 2-inch eyepiece is included, offering a magnification of 122x and a field of view of 89°. Our view of the yellow and blue stars of Albireo in Cygnus was glorious, with intense colours. The scope allows you to see down to mag. +14.7 and its 11-inch aperture resolves features to better than 0.5 arcseconds if conditions allow. A view of the Wild Duck Cluster, M11 in Scutum, showed a myriad of individual stars neatly separated. The scope’s optical excellence is complemented by the CGX-L, a belt-driven equatorial mount with computerised Go-To functionality. A NexStar+ hand controller provides the interface and after a simple two-star alignment we had our targets appearing in the central half of our field every time. A simple polar-alignment routine helped to refine the accuracy but we found that tracking wasn’t perfect every time, despite apparently good alignments. The CGX-L EQ 1100 EdgeHD is a big investment, but you get a serious system that’s suited to Solar System and deep-sky observing and imaging. For deep-sky imaging, it’s worth noting that the secondary on this scope can be replaced with a Fastar-compatible unit, converting the scope into a fast, f/2 imaging lightbucket. Imaging aside, the visual experience on offer is rich and rewarding.
VITAL STATISTICS • Price £7,199 • Optics Schmidt-Cassegrain aplanatic • Aperture 279.4mm (11 inches) • Focal length 2,800mm (f/10; f/7 with optional focal reducer; f/2 with third-party Fastar accessories) • Mount Celestron CGX-L German equatorial (load capacity 34kg) • Weight Tube 13kg, tripod 21kg, mount head 24kg • Included 23mm wide-angle 2-inch eyepiece, 9x50 finder • Supplier David Hinds • www.celestron.uk.com • Tel: 01525 852696
VERDICT
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William Optics GT71 apo refractor Fine views from this small-aperture telescope with a few luxury touches %DIƆHV
Focuser
Stray light must be dealt with to ensure good background contrast whether you’re using an eyepiece or a camera. In addition to the protective dew shield, the inside of the optical tube is lined with matte-black baffles, which help to do away with unwanted reflections and problems with scattered illumination.
A dependable focuser is a must for astrophotography, and this robust, 2.5-inch rack and pinion offering has stainless-steel internal reinforcement bars to prevent the drawtube flexing. A screw-on cover protects the fine focuser during transit and the chunky knobs are easy to use even with cold fingers.
Case Tube rings Dew shield Observing or imaging sessions are often frustratingly cut short by problems with dew on the lens, so we were pleased to see that the extending dew shield locks firmly in place with no chance of slipping back. The dew shield extends a full 10cm past the objective lens.
he GT71 certainly has luxurious looks, with its gold trim and classic white tube giving it an air of sophistication. What really matters, though, is the performance of the telescope, which, in this instance, came with an optional field flattening and reducing lens, the William Optics Flattener 6A adaptor. This has a dedicated spacing ring for the GT71 and Canon EOS fittings. Finding the perfect balance point on a mount can be tricky for little refractors with short dovetails, as there is limited room to position the tube rings, but the GT71 should work with most mounts, including travel-friendly types. Indeed, with its travel case and compact size – only 325mm when the dew shield is retracted – it would be an ideal companion telescope for travelling astronomers. Our first targets were the bright stars in Orion. These large, hot, blue stars will often
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Holding the telescope firmly is the job of the supplied black tube rings and gold Vixen dovetail, which complements the gold lens cap and tube trim. The rings have threaded holes on top for additional accessories such as a guide camera or finderscope and are easily adjusted using thumbscrews.
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A soft and padded carry case with detachable shoulder strap assists with the portability of this little refractor and protects it during travel or storage. Custom cut outs allow the telescope to be stowed with tube rings in place and there is room for an eyepiece or two, or field flattener.
highlight any optical issues, but the triplet lens system showed no signs of star bloating or unwanted reflection artefacts, demonstrating good colour correction and star shapes across the picture. Swapping a DSLR for a colour CCD, we were able to capture images of large targets, such as Markarian’s Chain in Virgo, Bode’s Galaxy and the Cigar Galaxy (M81 and M82) in Ursa Major. The GT71 allowed us to photograph these in context with a naturally coloured surrounding star field. Using a diagonal and 10mm eyepiece, we enjoyed excellent views with good contrast, even at 40x magnification. Our favourite view of the night was the whole of the Pleiades open cluster (M45), with a hint of nebulosity around Merope. Star shapes were sharp and good to the edge of the 72° field, providing us with a fine view of M81 and M82, even glimpsing NGC 3077 within the field of view.
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In a competitive arena, the GT71 brings a certain standard of luxury to the starting line up, with a convincing performance that will satisfy both astrophotographers and visual observers.
VITAL STATISTICS • Price £879 (tube only), £999 (including flattener) • Optics FPL 53 apochromat • Aperture 71mm (2.8 inches) • Focal Length 420mm (f/5.9) • Focuser Dual-speed rack and pinion with 1:10 fine speed • Extras Tube rings, dovetail, 1.25-inch adaptor, soft carry case • Weight 2.2kg • Supplier Widescreen Centre • www.widescreen-centre.co.uk • Tel 01353 776199
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Equipment reviews • best of 2017
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Sky-Watcher Star Adventurer Mini 7KLV OLWWOH OLJKWZHLJKW WUDFNLQJ PRXQW PDNHV D Ć…QH WUDYHOOLQJ FRPSDQLRQ Wi-Fi and app The tracking mount has a built-in Wi-Fi network that allows you to connect your smartphone or tablet to it and control the tracking and other aspects of the mount via the free Star Adventurer Mini app. It also allows you to control your camera via the snap port, however the correct camera remote cable is an optional extra.
PolarScope/ sight Polar alignment is achieved with a pair of lineof-sight holes for rough alignment, then with an integrated polarscope for accurate ďŹ ne-tuning. The polarscope can be lit with a small illuminator that ďŹ ts over the front of the unit or with the supplied adapter for when the L bracket is installed.
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Tracking mount body The main Star Adventurer Mini body is small enough to ďŹ t in your palm and weighs just 650g. It can be attached to a tripod, with latitude adjustment done via the tripod’s tilt head, or used with the supplied equatorial wedge.
Equatorial wedge The equatorial wedge provides greater exibility for levelling the mount on a tripod, with the included bubble level, as well as a wide range of latitude adjustment from 0-90°. Two adjustment bolts for azimuth make it easy to line up in the direction of the polar axis.
L Bracket and ball-head adaptor The supplied adaptor allows you to attach a camera directly to the mount or ďŹ t a ball head (sold separately) for a greater range of movement. For larger lenses, the dovetail L bracket provides better support and balance while an optional counterweight and shaft is useful for the heaviest lenses.
ky-Watcher has taken its Star Adventurer tracking mount and shrunk it to make an ideal travelling companion. It comes in two parts: a tracking mount, which weighs just 650g, and an equatorial wedge that tips the scales at 518g. Even though you can leave it behind if you need to travel light, the wedge provides solid support for the tracking mount, a bubble level and excellent adjustment for polar alignment. We’d always bring it along if astrophotography is on the cards. The tracking mount’s built-in Wi-Fi lets you to sync your smartphone or tablet to it and control its functions. The Star Adventurer Mini app (free for iOS and Android) is easy to use and has many functions. Its primary function, however, is to set the tracking rate, length and number of exposures. With a DSLR and 18-55mm kit lens set at 18mm, we were able to take a 10-minute exposure of Taurus and Auriga with barely any trailing evident until we zoomed right into the image. We then set the camera lens to 55mm and framed the Pleiades and Hyades and were able to take a five-minute exposure, again with barely any trailing. Sky-Watcher suggests a maximum lens of 100mm, but we found the unit could cope with bigger lenses, making this an ideal basic solar setup for eclipse chasers. Overall, the Star Adventurer Mini is a winning combination and a highly recommended piece of kit for budding astrophotographers who like to travel.
VITAL STATISTICS • Price £279 • Payload capacity 3kg • Latitude adjustment 0-90º • Tracking rates Sidereal, 0.5x sidereal, 2x sidereal, lunar, solar, no tracking (all via Wi-Fi) • Power requirements 2x AA batteries • Polarscope Polarscope with separate red-light illuminator • Extras L mounting bracket, built-in Wi-Fi, snap camera control port, 1/4–3/8-inch thread converter • Weight Mount 650g, wedge 518g • Supplier Optical Vision • www.opticalvision.co.uk • Tel 01359 244200
VERDICT
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Daystar Sodium D-Line 4XDUN H\HSLHFH ƅOWHU
Power port Plug in the power supply and wait for the temperature indicator light to go green; in winter, we found this could take up to 15 minutes. The filter can also run on a 1.5A/5V battery pack.
$ ƅOWHU WKDW UHYHDOV D OLWWOH XVHG ZDYHOHQJWK LV D ZHOFRPH DGGLWLRQ IRU VRODU DVWURQRPHUV 7HOHFHQWULF %DUORZ OHQV Designed for use on f/4 to f/9 refractors, this eyepiece filter delivers a final image of f/17 to f/38 with the built-in 4.3x telecentric Barlow. This internal system makes it four times more powerful than a standard solar scope.
LED A coloured LED shows how far the Quark is from its correct operating temperature. It starts off yellow and remains so for 5-10 minutes, turning green when the filter has settled to its required temperature and is ‘on band’ for viewing. Red indicates that not enough voltage is reaching the unit or that there is an electrical fault.
%DUUHO This filter has been designed to fit on most refractor-based telescopes and comes with 2-inch and 1.25-inch barrels. The 2-inch barrel has a cut-out to allow for a more precise 1.25-inch mounting.
Tuning knob The tuning knob adjusts the centre wavelength by 0.1A with each click, adding or subtracting contrast in the view. This can also be used to compensate for droop on the focuser.
sing the sodium wavelength of light for solar astronomy is not a new idea, but one considered to be quite exotic by amateur astronomers. Perhaps that will change now that Daystar has added a sodium D-line eyepiece filter to its Quark range. This is quite an exciting product for solar astronomers in the UK as it has a 589nm bandpass, a good area of the spectrum with respect to poor weather conditions or a low winter Sun. The changeable UK weather can cause all sorts of issues with solar astronomy – calcium, hydrogen-alpha and white light can produce poor results in mid-winter. By narrowing the wavelength, the Sodium D-Line eyepiece removes the unwanted parts of the light spectrum to provide a cleaner view of our star. Setup is easy: just attach the ultraviolet/ infrared-blocking filter to the front of a star diagonal and then insert the eyepiece filter.
ALL PICTURES: WWW.SECRETSTUDIO.NET
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We witnessed a reasonably sized sunspot for our first test, using the Quark with a 25mm eyepiece and a 6-inch, f/6 Altair Starwave refractor. The Sun appeared a nice yellow colour with crisp detail in and around the sunspot. But the view was quite bright, which led to a lack of granulation detail. In subsequent views with different equipment this remained the case. For imaging, we attached the eyepiece filter to a 5-inch Astro-Tech TMB-130 refractor and a few different cameras. We were impressed with the detail in the images considering the weather conditions. On the screen there was a lot more of the granulation detail that was missing when simply looking through the eyepiece, and when roving over the surface of the Sun it was easy to pick out the smallest sunspots, which would be hidden to a hydrogen-alpha setup. The detail around the larger sunspots, however, was very good and on
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the videos recorded it remained very stable. It did take a little playing around to get the most from the videos – we found that recording 1,000 frames for each and stacking the 100 top frames gave the best results. But the D-line Quark gave us more detailed images of sunspots then the calcium and hydrogen-alpha variants. It’s a pleasing addition to the Quark family.
VITAL STATISTICS • Price £999 • Barrel size 1.25-inch and 2-inch • Tuning range 589nm • Power 1.5A/5V USB • Extras Power supply, protective case • Weight 400g • Supplier Altair Astro • www.altairastro.com
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QHYCCD QHY367C &026 FRORXU FDPHUD
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$ ZHOO FRROHG RQH VKRW FDPHUD ZLWK H[FHOOHQW VHQVLWLYLW\ 3HOWLHU FRROLQJ The two-stage Peltier cooling system can reduce the operating temperature to 35Âş below the ambient temperature, providing a huge reduction in noise. The ambient temperature during testing was 14°C and a steady temperature of –15°C was easily achieved after ďŹ ve minutes.
$QWL JODUH FRDWLQJV There are anti-reection coatings on both sides of the optical window over the sensor, and this helps prevent star haloes. Note that the window does not have an infrared-cut coating, so a separate 2-inch screw-in ďŹ lter is recommended for Solar System imaging. This isn’t required for deep-sky imaging.
Threaded SRZHU VXSSO\ The threaded connector and provided cables prevent accidental power disconnections, which can occur with unthreaded connectors when you’re slewing. Disconnections can be problematic as the cooling system shuts down and needs to be re-enabled. A 12V power supply is not included.
86% connection
7HOHVFRSH connection and adjustment ring The M54 to 2-inch screw-threaded adaptor/ nosepiece allows the camera to be easily inserted into a 2-inch focuser. There is an M48 thread on the nosepiece so you can attach a ďŹ lter. The angle adjustment ring allows you to get the sensor precisely square to the image plane.
he QHY367C, is a highresolution CMOS device capable of Solar System imaging but primarily intended for deep-sky astrophotography. It uses Sony’s IMX094, one of the highest-resolution, full-frame (36 x 24mm) colour sensors available. The sensor is cooled by a two-stage TEC (Peltier cooling system), which provides cooling of up to 35º below the ambient temperature. This results in low noise and 14 stops of dynamic range. The resulting RAW file size of an individual exposure is almost 71MB, so the camera’s USB 3.0 connection is a welcome inclusion, providing short download times; in our case, less than two seconds for each full-frame capture. The 128MB DDRII image buffer acts as a cache to insure against frame loss, useful when shooting videos. Of course, this all means you need a powerful computer and one with a USB 3.0 port. The QHY367C is simple to use. Attach it to a 2-inch drawtube, then connect a 12V power supply and the USB 3.0 cable. There is no guide port, though, so an external guide system is needed for long exposures. After fixing it to a 4.5-inch reflector, we chose M13 in Hercules as our first target and found that our regular flattener/reducer produced serious vignetting. It didn’t have a large enough image circle to cover such a large chip. Once removed, the vignetting was dealt with by calibrating with flat frames. The cropped frame of our final stacked M13 image (showing only 10 per cent of the original frame area) had superb detail, including the propeller feature. With the 367C, QHY has produced an outstanding and versatile one-shot-colour camera that pushes the boundaries of definition and sensitivity for deep-space astrophotography.
The large ďŹ le size and high frame rates that can be generated by this camera require a high-speed connection to download images as fast as possible. This is particularly true when capturing video for lunar or planetary imaging and for the ‘live broadcast’ capabilities of the camera. A USB 3.0 cable is provided.
VITAL STATISTICS • Price £4,399 • Sensor Sony IMX094 CMOS • Pixels 7,376 x 4938 (4.88Οm square) • Resolution 36.4 megapixels • Exposure range 60 microseconds to 60 minutes • Read Noise 2.4e at unity gain • Dimensions 90mm diameter, 110mm long • Power 12V power adaptor 3.5A • Weight 788g • Extras USB 3.0 cable, power cable, 2-inch nosepiece, angle adjustment ring • Supplier Modern Astronomy • www.modernastronomy.com • Tel 020 8763 9953
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January
Orion is front and centre this month, and surrounded by an astounding array of sights
Key dates 2 JANUARY Tonight’s full Moon is a perigee full Moon and the brightest and largest for 2018
3 JANUARY Peak of the Quadrantids meteor shower – the Moon will interfere
7 JANUARY Jupiter and Mars appear 13 arcminutes apart this morning
12 JANUARY Ganymede and Europa’s shadows are both in transit from 05:30 UT
15 JANUARY Saturn, Mercury and a 2% waning crescent Moon form an attractive right-angled triangle this morning
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January 2018
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STARS & NEBULAE & OVERALL WINNER
The Rho Ophiuchi Clouds Artem Mironov (Russia)
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MOON PHASES Key stages in the monthly cycle
OPEN CLUSTER FIRST QUARTER MOON 24 Jan
NEW MOON 17 Jan
STAR NAME
FULL MOON 31 Jan
GLOBULAR CLUSTER PLANETARY NEBULA DIFFUSE NEBULOSITY DOUBLE STAR
VISIBLE PLANETS Where to spot the planets this month
VARIABLE STAR THE MOON (SHOWING PHASE) COMET TRACK
VENUS
MARS
JUPITER
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URANUS
NEPTUNE
Morning planet best at the start of January rising in the southeast a couple of hours before sunrise.
Difficult due to its proximity to the Sun. May be glanced briefly in the evening twilight at the end of January.
Appears close to Jupiter in the morning sky at the start of January.
Morning planet improving throughout the month. Appears very close to Mars on 6 and 7 January.
Morning planet never leaving the dawn twilight. Appears close to Mercury 12-15 January.
Evening planet, in the ‘V’ of Pisces at the start of January but loses altitude by the month’s end.
Evening planet, best seen at the start of January. Currently close to Lambda (h) Aquarii.
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January 2018
WorldMags.net January at a glance The hunter and his dogs pursue their prey across the night sky Magnificent Orion is well presented this month
alpha star of Canis Minor, the Little Dog is the most obvious marker to this pattern.
A hare, a bull and a crab
KEY TOhe long, cold nights of January provide an immersive stargazing STAR CHARTS
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naked eye, this causes Sirius to flicker and flash vibrant colours. Sirius is the brightest star in Canis Major, the Great Dog. The shape of the dog isn’t that easy to spot until you realise it’s running up the sky towards its master, Orion. The second of the two hunting dogs is represented by two stars to the northeast of Sirius. Here Procyon, the
experience but remember to wrap up warm. The most obvious constellation on view is Orion, the Hunter. Formed from seven bright stars, this is one pattern most people can recognise. Three bright stars in a line form the hunter’s belt and hanging below is Orion’s sword containing the Orion Nebula, a glowing gas cloud Moon easily seen with binoculars or a small telescope. Follow the line of Orion’s belt southeast to arrive at Sirius, the brightest night-time star of them all. Mercury From the UK, Sirius only ever manages to reach an Mercury, Saturn and a thin altitude of around 20° so crescent Moon low in the its light has to pass through southeast, seen here 50 minutes a thick, often turbulent before sunrise on 15 January layer of atmosphere. To the
Saturn
The two bright stars marking the shoulders of Orion are Betelgeuse in the northeast and Bellatrix in the northwest. Betelgeuse is a red giant star but looks orange to the naked eye. Joining the dots between Betelgeuse, Procyon and Sirius defines an asterism (unofficial pattern) known as the Winter Triangle. The Milky Way runs through the triangle intersecting the large and illdefined shape of Monoceros, the Unicorn. A binocular sweep through the triangle reveals some lovely open clusters. The bottom of Orion is marked by Saiph and brilliant Rigel. The colour contrast between orange Betelgeuse in the northeast and blue-white Rigel in the southeast is striking. Below Orion is a faint but distinctive pattern, resembling the infinity symbol. This is Lepus, the Hare, an unfortunate creature being chased for eternity by Orion and his two dogs. Follow Orion’s belt northwest to arrive at the bright orange star Aldebaran, marking the eye of Taurus, the Bull. The Bull’s face is depicted by a V-shaped pattern, part of the Hyades open cluster. Follow the line from Orion’s belt through Aldebaran to arrive at the Pleiades, or Seven Sisters, open cluster, which is also in Taurus. Extending the arms of the V-shaped Hyades to the east points to the stars marking the tips of the bull’s horns. The lower star, Zeta Tauri is a navigational aid for the telescopic supernova remnant known as the Crab Nebula. The upper horn tip is marked by Elnath, a relatively bright star that used to be part of the pentagonal constellation of Auriga located further north. Clearly defined by the bright star Capella at its apex, Auriga and Taurus are commonly shown on star charts joined at Elnath. Mid-January offers the darkest skies, there being two full Moon’s at the start and end of the month. The second full Moon in a month is often referred SE to as a ‘Blue Moon’ in popular culture.
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February Ganymede and Jupiter dance their way through the shortest month of the year
Key dates 8 FEBRUARY The Moon occults Gamma (a) Librae just after 03:00 UT
10 FEBRUARY Ganymede transits Jupiter’s disc from 02:30 UT
16 FEBRUARY Excellent thin Moon spotting opportunity this evening with Venus nearby
17 FEBRUARY Ganymede’s shadow transits Jupiter from 01:20 UT
24 FEBRUARY Another opportunity to watch Ganymede’s shadow transit Jupiter from 05:00 UT
WINNER AURORAE
Ghost World Mikkel Beiter (Denmark)
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February 2018
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FIRST QUARTER MOON 23 Feb
GLOBULAR CLUSTER PLANETARY NEBULA DIFFUSE NEBULOSITY DOUBLE STAR
VISIBLE PLANETS Where to spot the planets this month
VARIABLE STAR THE MOON (SHOWING PHASE) COMET TRACK
VENUS
MARS
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SATURN
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NEPTUNE
Moves into the evening sky at the end of the month when it’ll appear close to Venus.
Very bright planet best seen at the end of the month, low in the west after sunset.
Too small for telescopic viewing at present. Close to its celestial rival Antares on 9 February.
Morning planet reaches its highest altitude due south in darkness at the end of February.
Morning object slowly increasing its apparent distance from the Sun during February.
Evening planet, reasonably well positioned at the start of the month but losing altitude by the end.
Neptune is too close to the Sun for viewing this month.
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WorldMags.net February at a glance Orion departs the stage to make way for Gemini, Leo and Cancer
M
ighty Orion, the Hunter, is still prominent in February’s sky but his time is limited. The Northern Hemisphere’s spring equinox occurs on 20 March marking the time of year when the length of night is shortening at its most rapid rate. Consequently, enjoy Orion during February before he makes his rapid stage exit to the west. The winter Milky Way flows down the sky to the east of Orion and as it does so it clips the feet of Gemini, the Twins. The two principal stars of Gemini, Castor and Pollux, are easily located by extending a line from Rigel through Betelgeuse, both in Orion, for 1.5x that distance again. Castor and Pollux are easy to identify because they are bright and look similar, at least on first appearance. Look at them carefully and differences start to become evident with Pollux being slightly brighter than Castor and more orange in colour. The rest of the constellation is rectangular with Castor and Pollux marking one short side of the rectangle. The rest of the shape extends toward Orion. The two long sides of the rectangle depict the two stick figure bodies of the twins. With a bit of patience the entire figures are relatively easy to see and quite rewarding to pick out. Further east is the well-defined pattern of Leo, the Lion. The brightest star here is Regulus, which sits at the bottom of a backward question mark pattern known as the Sickle. This represents the front leg and head of the lion. From here, the lion’s rectangular body, pointed tail and dangling legs are relatively easy to imagine.
Ganymede will once again cast its large shadow on Jupiter’s disc on the mornings of 17 and 24 February
looks like a sideways tear-drop. This is the head of Hydra, the Watersnake. The rest of Hydra meanders southeast of the head,
Bees in the mist Look to the midpoint between Castor and Regulus and you may, depending on your sky clarity, be able to see mistiness here. This is the location of the Beehive Cluster, otherwise known as Praesepe, or M44. This magnificent open cluster is best viewed in a wide-angle instrument, such as a pair of binoculars. It sits right at the heart of the faint constellation of Cancer, the Crab, which appears like an inverted Y. Below Cancer is a more easily identified pattern that
Þ Venus should be obvious low in the southsouthwest 20 minutes after sunset on 16 February but can you see the 20.3-hourold lunar crescent, 1° below and to the left?
only managing to fully rise into the early hours of the morning. Hydra is the largest constellation by area in the entire sky. North of Leo you’re heading into the southern regions of Ursa Major, the Great Bear. Before you get there, however, there’s a small diamond-shaped pattern that represents Leo Minor, the Little Lion. This constellation is less easy to pick out than Leo itself and adjoins another faint pattern to the northwest, known as Lynx. It’s said that Johannes Hevelius named this constellation because you’d need eyes as good as a lynx’s to see it! At this time of year, that most identifiable pattern of stars forming what’s known as the Plough, or Saucepan, can be seen moving ever closer to the position directly above your head, known as your zenith. Early evening it can be seen in the northeast balancing on the tip of its handle. The two stars furthest from the handle are known as the Pointers because when you extend the line they make away from the base of the Plough’s blade (the bottom of the saucepan) they point towards the Pole Star, Polaris.
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March
The Blue Moon makes its second appearance of the year at the end of the third month
Key dates 1 MARCH Full Moon occults Regulus just after 06:00 UT as they set in the west
5 MARCH Venus and Mercury appear 1.4° apart low in the west after sunset
18 MARCH Venus, Mercury and a 1% waxing crescent Moon form a line this evening
22 MARCH The Moon occults Aldebaran shortly after 23:30 UT
25 MARCH Callisto passes north of Jupiter’s disc while Ganymede transits this morning
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March 2018
WorldMags.net WINNER OUR MOON
Blue Tycho Lรกszlรณ Francsics (Hungary)
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March 2018
WorldMags.net March at a glance The Milky Way slides out of view to reveal galaxies far, far away The Leo triplet, located in the back leg of Leo the Lion, comprises M65, M66 and hamburger-shaped NGC 3628
well. From the UK they are low, only reaching around 18° above the horizon. The pattern formed by the four brightest stars in Corvus is known as the Sail.
Circles and triangles
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ith the arrival of spring, the night sky takes on a far more subtle appearance. This is due to the Milky Way rotating out of view so we’re now looking out at right-angles to our Galactic plane into deep space. For this reason, we lose many of our Galaxy’s local deep-sky KEY TO objects; these are replaced by the less bright but equally impressive galaxies that lie STAR CHARTS beyond the Milky Way. The constellation of Leo, the Lion, takes centre stage, easily identified thanks to its distinctive Sickle asterism, which marks the lion’s head and foreleg. Close to Leo’s forward-pointing rear leg is the M96 group of galaxies. These are visible through a small telescope as faint, mostly elliptical smudges. A far more impressive group lies close to Leo’s rear or eastern back leg. Known as the Leo triplet, this consists of M65, M66 and NGC 3628. The galaxies are relatively bright and interesting because they have different shapes. Although Leo contains lots of galaxies, the largest collection lies next door in the sprawling constellation of Virgo, the Virgin. Virgo’s shape is like a rectangle with a large semi-circular arc – the Bowl of Virgo – balancing on the rectangle’s northwest corner. The open shape of the bowl encompasses what’s known as the Virgo
North of the Bowl of Virgo is a beautiful smattering of stars in the shape of a triangle. These stars are part of the open cluster Melotte 111, which itself is part of Coma Berenices, otherwise known as Queen Berenices’ Hair. The Plough, or Saucepan, lies to the north of Coma Berenices and is virtually overhead around midnight at this time of year. If you imagine the handle of the Plough as part of a circle, the circle’s centre is marked by the star Cor Caroli, the brightest star in Canes Venatici, the Hunting Dogs. Extend the arc of the handle of the Plough away from the blade and you’ll eventually arrive at Arcturus, the brightest night-time star in the northern half of the sky. The brightest night-time star Cluster. A sweep through the of all is Sirius, but this sits region using a telescope south of the Celestial fitted with a lowEquator. Arcturus is power eyepiece the brightest star reveals many in the spring faint smudges constellation here. Using of Boötes, the detailed Herdsman, charts, it’s who looks quite an after Ursa experience Major, the to ‘galaxy Great Bear, hop’ from and Ursa one galaxy Minor, the to the next. Little Bear. Below Leo Stargazing and Virgo lies the is made a little elongated body of harder from the Hydra, the Watersnake. UK this month with Hydra appears to be the start of British Þ The Moon is full on 2 and 31 March. Summer Time on carrying a number of A second full Moon in a calendar smaller constellations 25 March. The Northern month is known as a ‘Blue Moon’, on its back. Close to Hemisphere’s spring, although its colour doesn’t change Hydra’s brightest star, or vernal, equinox Alphard, lies Sextans, the Sextant, a faint occurs on 20 March, representing a time and indistinct constellation made from when the length of night is shrinking at three stars close to the threshold of nakedits fastest for the year. eye visibility. Further east lays the more There’s also a repeat of the situation distinctive Crater, the Cup. Further east in January that meant two full Moons still is Corvus, the Crow, a small appeared in one month. The second full constellation containing four middleMoon on 31 March is a so-called ‘Blue brightness stars that stand out surprisingly Moon’, the second of 2018.
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Winter 2018
WorldMags.net “M41 may have been reported by Aristotle as a faint, naked-eye object as far back as 325 BC”
Stats NAME AND CATALOGUE REFERENCE: Messier 41 CONSTELLATION: Canis Major OBJECT TYPE: Open cluster VISUAL BRIGHTNESS: Mag. +4.5 (naked eye) DISTANCE: 2,300 lightyears APPARENT SIZE: 38 arcminutes PHYSICAL SIZE: 26 lightyears across BEST TIME TO SEE: 1 Jan 00:00 UT, 1 Feb 22:00 UT, 1 Mar 20:00 UT
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The M41 cluster is packed with bright stars, many of which display obvious colour
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M41
Open cluster in Canis Major Although lying low in the early part of the year, M41’s many bright and coloured stars are a highlight of the winter sky NAKED EYE
The view from the ground
Messier 41 is an open cluster located within Canis Major, the Great Dog. It’s in a fairly low part of the sky where it reaches an altitude about 16° up as seen from the centre of the UK. This might be why it tends to get overlooked as a naked-eye object. Despite being mag. +4.5, its brightness is degraded by the thicker layer of atmosphere low down. Consequently it becomes difficult to see unless you’re in a very dark location. Finding M41 is easy because it’s 4°, or eight apparent Moon diameters, south of Sirius. As a guide, the width of your little finger at arm’s length is 1°. Before attempting to locate M41, give your eyes at least 20 minutes in total darkness so that they can become properly dark adapted.
Sirius
M41
CEDIC TEAM/ CHRISTOPH KALTSEIS/WWW.CCDGUIDE.COM, PETE LAWRENCE X 3
BINOCULARS Getting a closer look M41 is an easy target for a pair of binoculars. Its proximity to Sirius means that both objects will fit into the field of view of an average pair of binoculars with Sirius at the top of the field. Due to its southerly declination, it is best to let M41 get to its highest position, due south, in order for the cluster to climb into as clear a sky as possible. Only then will you get to experience its true beauty. Binoculars will show about six stars scattered over a gently glowing background formed by the cluster’s fainter members. The apparent size of M41 is 38 arcminutes, giving it a diameter almost one-third larger than the apparent size of the Moon. The mag. +6.0 star, 12 Canis Majoris, lies 21 arcminutes southwest of the centre of M41.
TELESCOPE Seeing all the detail A telescope trained on M41 reveals many stars. Through a 6-inch scope, approximately 50 cluster members ranging from mag. +8.0 – +12.0, pepper the field of view. The cluster contains around 100 members and a number of the brighter ones show obvious colour. Very prominent are the four bright yellow stars close to the heart of M41. These contrast nicely with a curving group of bluer stars arcing from south to west. The cluster’s large apparent diameter merits using a low power to keep everything in the field of view; too much magnification and the cluster loses visual impact. M41 is estimated to be 190–240 million years in age. It may have been reported by Aristotle as a faint, naked-eye object as far back as 325 BC.
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April
A packed month of highlights ends with the Lyrid meteor shower and Venus passing close by the Pleiades
Key dates 1 APRIL Very brief double shadow transit on Jupiter at 01:08 UT
2 APRIL Mars and Saturn appear very close in this morning’s sky
22 APRIL The lighting effect known as the Lunar X can be seen at 20:40 UT
22/23 APRIL Lyrid meteor shower reaches its peak
29 AND 30 APRIL Moon’s libration favours its southeast limb
WINNER PLANETS, COMETS & ASTEROIDS
Venus Phase Evolution Roger Hutchinson (UK)
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April 2018
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April 2018
WorldMags.net April at a glance The Plough points the way to the best sights this month
The lunar X may be seen on the night of 22 April, fully formed at 20:40 UT. Look for it using a telescope, one-third of the way up the Moon’s terminator from the southern limb
T
he recent Northern Hemisphere spring equinox on 20 March and the onset of British Summer Time on 25 March, mean getting a good view of the night sky is harder than it was during the previous months. Not all astronomy relies on the night sky, though, and for those who love to observe the Sun through a certified KEYsafety TOfilter, April sees our nearest solar star climbing to a decent height above STAR CHARTS the horizon and out of the turbulent air found at lower altitudes. During the nights in April, the Plough is located virtually overhead and can be used to find other stars and constellations. Imagine the pattern as a saucepan and extend the side nearest the handle southwest. Keep going approximately 10 times that distance to arrive at Regulus, the brightest star in Leo, the Lion, and the dot of the backward question mark pattern known as the Sickle.
Minor, the Little Bear. This is also the Pole Star around which all other stars appear to rotate each day. Ursa Minor does look a bit like a smaller version of the Plough except that its handle appears to curve up. Between the Saucepan and Ursa Minor lies the tail of Draco, the Dragon. This curves around the equivalent of the pan in Ursa Minor before arcing back towards the Moon phase
22 April
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Out of the pan Follow the arc of the saucepan’s handle away from the pan to arrive at the orange star Arcturus, the brightest in Boötes, the Herdsman. Keep the arc going and eventually you’ll arrive at the bright white star Spica in Virgo. Extend the side of the pan furthest from the handle north to arrive at Polaris, the brightest star in Ursa
constellation of Hercules, the Strongman. The head of Draco is marked by four stars forming a pattern known as the Lozenge. Returning to Arcturus, this star marks the pointed end of the kite-shaped constellation of Boötes. The kite is about as tall as the Plough is long. Look to the east where the kite appears to widen and you’ll see a small ‘C’-shaped pattern representing the constellation of Corona Borealis, the Northern Crown. This is a lovely grouping with the brightest star, Alphecca or Gemma, marking the sparkling jewel in the crown. Imagine the arc of the Plough’s handle as part of a circle and its centre can be identified by the middle-brightness star Cor Caroli, the brightest in Canes Venatici, the Hunting Dogs. If you have binoculars or a telescope, aim at the point mid-way between Cor Caroli and Arcturus, and you should be able to make out the globular cluster Messier 3. Canes Venatici requires imagination to see as a pair of dogs, as only two stars form the main pattern. The other star, Chara, lies to the northwest of Cor Caroli. Draw a line from Chara towards Alkaid at the end of the Plough’s handle, and in the area about four-fifths of the way along this line sits Messier 51, the Whirlpool Galaxy, best seen through a telescope.
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Þ The April Lyrid meteor shower peaks on the night of 22/23 April and will be best seen in the early hours of Monday the 23rd
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WorldMags.net WINNER ROBOTIC SCOPE
Encounter of Comet and Planetary Nebula Gerald Rhemann (Austria)
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May 2018
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May Watch Ganymede and its shadow take turns playing follow the leader across the face of Jupiter this month
Key dates 5 MAY Eta Aquariid meteor shower reaches its peak
6 MAY Ganymede chases its shadow across Jupiter’s disc from 20:50 UT
9 MAY Jupiter reaches opposition
14 MAY Ganymede precedes its shadow across Jupiter’s disc 00:30 UT
17 MAY Venus and a 7% waxing crescent Moon appear close in the evening twilight
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NEW MOON 15 May
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FIRST QUARTER MOON 22 May
CONSTELLATION NAME GALAXY
MOON PHASES Key stages in the monthly cycle LAST QUARTER MOON 8 May
STAR NAME
GLOBULAR CLUSTER PLANETARY NEBULA DIFFUSE NEBULOSITY DOUBLE STAR
VISIBLE PLANETS Where to spot the planets this month
VARIABLE STAR THE MOON (SHOWING PHASE) COMET TRACK
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Mercury isn’t well placed, barely creeping above the east-northeast horizon by sunrise.
A dazzling evening twilight planet, setting nearly three hours after sunset on 31 May.
Visible in the morning sky as it appears to move from Sagittarius into Capricornus.
Jupiter reaches opposition on 9 May and is at its best for the year, visible all night long.
Saturn is visible low towards the south in the early hours of the morning.
Not visible this month.
Not visible this month.
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May 2018
WorldMags.net May at a glance Jupiter makes its presence felt by sitting on the scales
T
he nights really start to shorten during May, making stargazing that bit harder. This year May sees the planet Jupiter located inside the constellation of Libra, the Scales. For those of us in the Northern Hemisphere, its appearance here has a bittersweet taste as it’s now starting to get rather low in our skies, barely scraping 20° of altitude. With Mars and Saturn also sharing a similar, if not worse, low situation, seeing the brighter planets is something of a struggle for mid-northern latitudes at present. Jupiter reaches opposition on 9 May but Ganymede transits Jupiter on 6 and 14 May, either side of opposition, which produces an interesting effect. On 6 May, Ganymede appears to chase its shadow across the planet’s disc. But on the 14th the orientation is reversed with Ganymede now preceding its shadow. In terms of the stars, Boötes, the Herdsman, now holds centre stage. Boötes has the shape of a kite with bright orange Arcturus as the pointed base. Off the eastern shoulder of the kite lies the semi-circular pattern of Corona Borealis, the Northern Crown. This pretty pattern is easily identified once you realise the crown’s diameter is slightly smaller than the length of the base of the nearby KEY TO Plough’s blade; you’ll find the Plough almost early evening. STARoverhead CHARTS
The beautiful semicircle of Corona Borealis sits close to the kite-shaped constellation of Boötes
BOÖTES
Arcturus Gemma
CORONA BOREALIS
the Serpent Bearer. Rasalhague marks the position of the serpent bearer’s head. Virgo, the Virgin, occupies the area to the south and southwest of Boötes. Despite being the second largest constellation, Virgo isn’t particularly easy to make out apart from its brightest star, Spica and
Hercules marches on East of Corona Borealis lies the sprawling and indistinct constellation of Hercules, the Strongman. Its saving grace is a pattern of four faintish stars that form the Keystone asterism, which manages to stand out surprisingly well. Depicted as a stick figure on a star chart, Hercules looks as if he’s marching from east to west with his club held high. This is misleading because the intended representation has the strongman upside-down as seen from the Northern Hemisphere. His head is marked by the middle-brightness star Rasalgethi, which sits close to the southern boundary of the constellation near to another ‘head’ star known as Rasalhague, the brightest star in the large, and again, ill-defined constellation of Ophiuchus,
Þ Jupiter reaches opposition this month, a time when it’s best presented for observing through a telescope
the large semi-circular pattern located to the northwest, called the Bowl of Virgo. Libra lies to the southeast of Virgo and is best identified by two stars with the wonderful names of Zubeneschamali and Zubenelgenubi meaning the Northern and Southern Claws respectively. The reason Libra appears to have claws is because it used to be part of the neighbouring constellation of Scorpius, the Scorpion, which now follows Libra across the sky. The area between Libra, Corona Borealis and Hercules contains half of the constellation of Serpens, the Serpent. Serpens is unique in the heavens because it has been split into two parts known as Serpens Cauda, the Serpent’s Tail, and Serpens Caput, the Serpent’s Head. The part between Libra, Corona Borealis and Hercules is the serpent’s head. The split occurs as Serpens crosses Ophiuchus, who is depicted carrying the beast across the sky. Serpens Caput is a zig-zag affair stretching up from the southwest corner of Ophuichus towards Corona Borealis. One standout deep-sky object here is the beautiful globular cluster M5, which sits between Serpens Caput and Virgo.
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June
Hercules and Serpens Caput show off their candidates for the best globular cluster in the northern sky
Key dates ALL MONTH June is an ideal month to keep an eye out for noctilucent cloud displays
1 JUNE This morning’s 94% waning gibbous Moon is less than a degree north of Saturn
18 JUNE Ganymede’s shadow transits Jupiter from 20:50 UT
23 JUNE Tonight’s 83% waxing gibbous Moon appears close to Jupiter
27 JUNE Saturn reaches opposition
WINNER SKYSCAPES
Passage to the Milky Way Haitong Yu (China)
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June 2018
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June 2018
WorldMags.net June at a glance Clear skies could showcase some stunning clouds and clusters
NLCs are most likely to be seen in the late evenings and early mornings from late May through to early August
T
he Northern Hemisphere’s summer solstice occurs on 21 June, when at 10:07 UT the Sun reaches its most northerly position in the sky. Consequently, our star never sinks that far beneath the northern horizon at night and it never becomes really dark. The earliest sunrise for the year occurs on 17 June, while the latest sunset on 25 June. There’s still plenty to see though. June and July are regarded as the best months to see the rare phenomenon known as KEY TOclouds, or NLCs. Although noctilucent these are CHARTS atmospheric, their origins are STAR linked to space. They are the highest clouds on Earth consisting of tiny ice crystals forming predominantly around the particles left behind when meteoroids vaporise in the atmosphere as meteors. NLC season runs from late May through to early August. If a display is in progress it can normally be seen 90–120 minutes after sunset low in the northwest or a similar time before sunrise low in the northeast. The best placed constellation on view at this time of year is Ophiuchus, the Serpent Bearer, which is located to the south. It’s prominent because its ill-defined form appears to create a void in the sky carving out a shape that’s often described as an upturned flowerpot. To the south lies the bright orange star Antares, the brightest in Scorpius, the Scorpion. This magnificent constellation is cut off in its prime by the southern horizon in the UK though. We get to see Antares, the scorpion’s heart, and its
claws fairly well. But it’s curving body and sting barely rise for most of the UK and the impact of the two close stars marking the stinger is sadly lost.
The greatest globular? North of Ophiuchus is Hercules, the Strongman, a difficult to make out constellation saved by the Keystone asterism. It’s supposed to resemble the shape of the stone used to lock arches in place and works well as a guide to identifying Hercules. Pointing a telescope at the spot one-third down the Keystone’s western edge will bring the globular cluster Messier 13 into view. This is often said to be the best example of a globular cluster visible in the northern half of the sky. M5 in Serpens Caput, the Serpent’s Head, gives it a run for its money though, so take a look at both and decide which one you think is best. Three bright planets join the scene this month: Mars in the southeast, Jupiter in the southwest and Saturn in between. All three are low for UK viewing and their appearance through a telescope won’t show them at their best. Saturn reaches opposition at the end of the month where it lies close to the Teapot asterism, which is part of Sagittarius, the Archer. In the nights around opposition, the planet’s rings can appear to brighten, a phenomenon known as the Seeliger, or Opposition, Effect. Steely white Vega, the brightest star in the constellation of Lyra, the Lyre, is close to the overhead point this month. A lyre
is similar to a harp and the shape of the instrument can be seen southeast of Vega. The magnificence of the summer Milky Way is beginning to make its presence felt during June but battling the bright twilight skies around the summer solstice it is easily lost from view. 18 June 21:55 BST (20:55 UT)
Jupiter
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Ganymede’s shadow just starting to become visible
18 June 22:45 BST (21:45 UT)
Ganymede’s shadow around mid-transit 18 June 23:35 BST (22:35 UT)
Ganymede’s shadow near to the end of transit
Þ Ganymede’s shadow can be seen crossing the northern part of Jupiter’s disc on 18 June, the event starting as the sky is beginning to darken
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Spring 2018
WorldMags.net “When looking at M3, it’s astonishing to realise that you’re observing a gravitationally bound collection of about half-a-million stars”
Stats NAME AND CATALOGUE REFERENCE: Messier 3 CONSTELLATION: Canes Venatici OBJECT TYPE: Globular cluster VISUAL BRIGHTNESS: Mag. +6.2 (binocular) DISTANCE: 33,900 lightyears APPARENT SIZE: 18 arcminutes PHYSICAL SIZE: 760 lightyears across BEST TIME TO SEE: 1 Apr 01:00 BST, 1 May 23:00 BST, 1 Jun 00:00 BST
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Seen through a 250mm telescope the brightest part of M3’s core measures about 5 arcminutes across with the outlying regions extending to an apparent diameter 18 arcminutes across
M3
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Globular cluster in Canes Venatici Ancient, vast and beautiful, M3 is easily hidden and often overlooked but it’s astonishing views are worth seeking out BINOCULARS Getting a closer look M3 is a beautiful globular cluster located close to the southern border of Canes Venatici, where it neighbours Boötes. Its position in the sky doesn’t place it immediately near any bright stars or strong shapes, and this may contribute to it being somewhat overlooked. The simplest way to locate it is to draw a line between Arcturus (Alpha (_) Boötis) and Cor Caroli (Alpha Canum Venaticorum). M3 lies at the mid-point of this line. Binoculars show the central, 10 arcminute core of M3 as a smudge. Under dark conditions, the core appears surrounded by a lighter region. This results in the cluster’s outer edge being rather loose. Be warned: light pollution is very good at hiding M3.
SMALL TELESCOPE Get more detail
BERNHARD HUBL/WWW.CCDGUIDE.COM, PETE LAWRENCE X 3
The loose outer-regions of the cluster become more visible with a small telescope, producing a low- to medium-power appearance that shows a bright central core surrounded by a glowing halo. Most globular clusters benefit from higher magnifications but be careful not to overdo it with M3 and make it harder to see. A power between x150 to x200 should resolve many of the cluster’s outer stars. Look carefully and you’ll see that it’s not circular but oval. There are beautiful star-strings here too, many start close to the core and extend into the outer halo as curving arcs. When looking at M3, it’s astonishing to realise that you’re observing a gravitationally bound collection of about half a million stars.
LARGE TELESCOPE See it all A large telescope will show M3 in all its glory. The cluster’s brightness, size and loose outer regions work together to bring you a breathtaking view that easily rivals that of M13 in Hercules – often cited as the best globular visible in the northern half of the sky. A 250mm telescope, using a highpower magnification, will virtually resolve the cluster right to the core. The oval shape of the core is apparent through larger apertures with the brighter centre offset towards the west. M3 is an ancient object, estimated to be around 8 billion years old – about twice as old as the Sun! It also contains the highest number of variable stars of any globular cluster, with at least 274 identified.
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July
The Moon and Mars pair up to put on a show close to the horizon at the month’s end
Key dates ALL MONTH July is an ideal month to watch for noctilucent cloud displays
6 JULY Earth is at aphelion, farthest from the Sun at 152,096,156km (94,508,170 miles)
27 JULY The full Moon rises totally eclipsed by the Earth’s shadow
27 JULY Mars reaches opposition
28 JULY Peak of the Delta Aquariid meteor shower under Moonlight interference
WINNER YOUNG ASTRONOMY PHOTOGRAPHER OF THE YEAR
Saturn Olivia Williamson (UK – aged 13)
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July 2018
WorldMags.net July at a glance The Summer Triangle and Northern Cross take centre stage Eclipse timings‌ Start of penumbral eclipse (P1): 17:15 UT Start of umbral eclipse (U1): 18:24 UT Start of totality (U2): 19:30 UT Moonrise (centre of UK): 20:08 UT Sunset (centre of UK): 20:12 UT Maximum eclipse: 20:22 UT End of totality (U3): 21:13 UT End of umbral eclipse (U4): 22:19 UT End of penumbral eclipse (P4): 23:29 UT
Mars SE
Sunset
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Þ The Moon rises while inside the Earth’s shadow on 27 July while Mars follows in the background
T
he Northern Hemisphere’s summer solstice occurs on 21 June and from much of the UK the start of July can be a frustrating time for astronomy. The days and weeks around the solstice produce night-time skies that never get truly dark, a problem that gets worse the further north you are. But, towards the end of the month a short period of true darkness does return for many. KEY TO Rather frustratingly in 2018, the return of dark skies during late July will be STAR CHARTS marred by the presence of a bright Moon. However, the full Moon that occurs on 27 July will rise fully eclipsed as seen from the UK, the first totally eclipsed Moon seen since 28 September 2015. The summer sky is dominated by a large asterism known as the Summer Triangle. This is formed from three bright stars: Vega in Lyra, the Lyre; Deneb in Cygnus, the Swan; and Altair in Aquila, the Eagle. Vega is the first to appear after sunset and virtually overhead as darkness descends. Lyra depicts a musical instrument similar to a harp, the main body of which is represented by a squashed diamond of stars southeast of Vega. The two stars at the base of the diamond act as a navigational aid to a deep-sky object much loved by amateur astronomers, the Ring Nebula, M57. The nebula sits slightly south of a point two-fifths of the way from Sheliak (Beta (`) Lyrae) to the west,
towards Sulafat (Gamma (a) Lyrae) to the east. You’ll need a telescope to see M57.
From swans to wild ducks Deneb marks the top of another large, summer asterism known as the Northern Cross. The cross is almost as tall as the Plough is long and formed by the central stars of Cygnus. The bottom star of the Northern Cross is Albireo (Beta (`) Cygni), a star that represents Cygnus’s beak. This is another summer favourite because a
telescope trained on Albireo will reveal a beautiful pair of stars, one of which is a warm yellow and the other an azure blue. Altair, the most southerly star in the Summer Triangle, is easily identified as it’s flanked by two prominent stars on either side. The southern end of Aquila marks the eagle’s tail and ends with a small arc of stars, some belonging to neighbouring Scutum, the Shield. Towards the end of the arc lies the Wild Duck Cluster, Messier 11. This is a truly stunning sight through the eyepiece of a telescope as it’s extremely rich in faint stars. The summer Milky Way flows down through the Summer Triangle. As it approaches the UK’s southern horizon, a thicker layer of atmosphere diminishes the grandeur of our Galaxy’s bright core, which lies in this direction. How much of this you can see really depends on the clarity of your sky low to the south. If you look hard enough, you might be able to make out the asterism known as the Teapot in this region. This year, Saturn lies just to the north of the top of the lid. The Teapot is part of Sagittarius, the Archer. If you can identify it, scan the area where the steam would be rising from the spout using a pair of binoculars. Here lie a multitude of spectacular deep-sky objects including M8, the Lagoon Nebula and M20, the Trifid Nebula. M17 M18
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August
Jupiter’s moons put on a dazzling display as a prelude to the Perseid meteor shower
Key dates 2 AUGUST Jupiter’s moons Io and Europa do a double shadow transit between 20:15 and 21:05 UT
7 AUGUST Jupiter appears to have an extra moon as it passes a ninth-magnitude star this evening
12/13 AUGUST Peak of the annual Perseid meteor shower under favourable conditions
14 AUGUST Venus and a 15% waxing crescent Moon appear close shortly after sunset
26 AUGUST Mercury has its best morning appearance for 2018
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August 2018
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WINNER PEOPLE & SPACE
Wanderer in Patagonia Yuri Zvezdny (Russia)
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August 2018
WorldMags.net August at a glance August’s highlight is a very favourable Perseid meteor display `
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fter the bright, twilight nights of early July, the latter part of that month re-introduces the UK to true darkness once again. Unfortunately, this period in 2018 is compromised by a bright Moon. But there is a positive side to this as the full Moon, which occurs on 26 July, means the sky is good and dark from the second week of August, offering perhaps the best opportunity to view the summer Milky Way from the UK. August also sees the annual Perseid meteor shower. This is one of the more reliable showers, reaching peak activity on the night of 12/13 August. In 2018 this peak activity will coincide with moonless conditions and, if the skies are clear, it will be a spectacle worth watching out for. Under dark-sky conditions, between 40-50 meteors per hour may be seen visually. This figure will drop off fast if the sky is hazy or light polluted, so it pays to plan ahead. The Perseids can also include some good bright trails that record well with a camera.
From the fox to the foal The Summer Triangle is formed from the three bright stars, Vega, Altair and Deneb, the brightest stars in Lyra, Aquila and Cygnus respectively. These large, bold constellations contrast with a progression of smaller patterns that begins near to the star Albireo, in the Summer Triangle. Vulpecula, the Fox, is the first and is faint and ill-defined. Despite this, Vulpecula contains the Dumbbell Nebula, Messier 27, one of the true showpieces of the summer sky. Southeast of Vulpecula lies Sagitta, the Arrow, a more distinctive pattern that resembles a small arrow. Just south of the mid-point of the arrow’s shaft lies the loose globular cluster M71. Keep heading southeast and you’ll arrive at the constellation of Delphinus, the Dolphin. It may not look too much like a dolphin at first, but the chosen name starts to make sense when you realise that the main shape represents the head and neck of a bottle-nosed dolphin. The progression ends further to the southeast of Delphinus with the small quadrilateral pattern known as Equuleus, the Foal. This is a rather indistinct constellation difficult to discern and overshadowed by the large equine pattern
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to the east representing the constellation of Pegasus, the Flying Horse. To the south, the most obvious object looks like a brilliant orange star. This is actually the planet Mars, which is moving between the Teapot asterism in Sagittarius,
the Archer, and the large triangular pattern of Capricornus, the Sea Goat. Finally, a tiny partial eclipse of the Sun can be seen between 08:30–09:00 UT on 11 August. This will be only visible from the extreme north of Scotland. Most of the Milky Way’s core is visible from the UK, but diminished due to low altitude. This shot was taken from Utah, in the US, at a latitude of 38º
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September The comet 21P/Giacobini-Zinner carves its way across Septemer’s night skies
Key dates 2/3 SEPTEMBER Binocular comet 21P/Giacobini-Zinner passes 1° from Capella
3 SEPTEMBER A double transit of Io and Europa’s shadows occurs between 18:25-19:10 UT in twilight
7 SEPTEMBER Neptune reaches opposition
17 SEPTEMBER Saturn appears 1.6° southwest of a 57% waxing gibbous Moon at 19:00 UT
25 SEPTEMBER Tonight’s full Moon is the Harvest Moon for 2018
WINNER OUR SUN
Mercury Rising Alexandra Hart (UK)
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September 2018
WorldMags.net September at a glance 6HSWHPEHUĹ?V VNLHV DUH Ć…OOHG ZLWK FLUFOHV WULDQJOHV DQG VTXDUHV Positions correct for 00:00 UT on shown date Capella
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Procyon
27 Sep
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Rosette Nebula
ORION Betelgeuse
MONOCEROS 1 Oct
Ăž Seventh-magnitude comet 21P/Giacobini-Zinner encounters several key background deep-sky objects throughout September
T
he Northern Hemisphere’s autumn equinox occurs on 23 September, so this is the time of year when the nights are growing longer at their fastest rate. The full Moon on 25 September is the closest to this equinox making it the Harvest Moon for 2018. The Summer Triangle is beginning to drift west but will continue to remain obvious right up to the end of the year. To the east of the triangle, the stars of autumn are ready to take centre stage. The most obvious pattern here is the Great Square of Pegasus. Despite being neither strictly a square, nor formed from four stars in Pegasus, it’s a distinctive pattern that can be used to locate other stars and constellations.
The square and the circlet The Square’s sides are all of unequal length. The southern edge is longest at 16.5° and the western edge the shortest at just under 13°. It helps to remember that your fist at arm’s length is about 10° wide. It also helps to know that the Great Square’s bottom edge is only parallel to the horizon when the square is due south. When closer to the eastern or western horizon, it appears rotated as a diamond.
Pegasus, the Horse, is upside down as seen from the UK. The head is formed from a squat, down-pointing isosceles triangle southwest of the Great Square. To the north of the head lie the scattered stars depicting the horse’s forelegs. The most distinctive pattern here is a small equilateral triangle
formed with the Great Square’s northwest corner star, Scheat. Head north from this equilateral triangle and the next group of mostly faint stars you’ll find is Lacerta, the Lizard. Study this area carefully and you should be able to see a fainter and smaller version of the W-shaped constellation of Cassiopeia, the Seated Queen. South of the Great Square is a smaller pattern called the Circlet, which is part of the constellation of Pisces, the Fish. Despite its name, the pattern is more like an ellipse of fainter stars, the longest axis is slightly shorter than half the length of the Great Square’s southern edge. A line of faint stars extends east from the Circlet towards middle-bright Alrescha, the brightest star in Pisces. The line then turns northwest towards Andromeda, the Chained Princess. The Circlet represents one of the two fish of Pisces. The second lies just south of Andromeda, appearing as an indistinct, faint triangle. The bright star Capella can be seen low towards the north early evening, climbing higher in the early hours of the morning. Comet 21P/Giacobini-Zinner passes within 1° of the star on the night of 2/3 September. This month, the comet will appear at its brightest as it passes closest to the Earth on 10/11 September. At this time 21P/ Giacobini-Zinner should be around mag. +7.0, making it an easy binocular target.
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Ăž Neptune reaches opposition on 7 September and throughout the month can be seen heading in the direction of Lambda (h) Aquarii WWW.SKYATNIGHTMAGAZINE.COM
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Summer 2018
WorldMags.net “In photographs, the Pillars of Creation form a second, smaller HDJOH VHHQ LQ SURÆ…OH DQG FOXWFKLQJ D Æ…VK LQ LWV WDORQVÅ
Stats NAME AND CATALOGUE REFERENCE: Eagle Nebula, Messier 16 CONSTELLATION: Serpens Cauda OBJECT TYPE: Open cluster with nebulosity VISUAL BRIGHTNESS: Mag. +6.4 (binocular) DISTANCE: 7,000 lightyears APPARENT SIZE: 7 arcminutes PHYSICAL SIZE: Cluster diameter 15 lightyears, nebula extends out to 75x55 lightyears BEST TIME TO SEE: 15 Jul 00:00 BST, 15 Aug 22:00 BST, 15 Sep 20:30 BST
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Contained within the three Pillars of Creation are the materials needed for the formation of new stars
M16
L A N TS SO E A RG SE TA
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Open cluster with nebulosity in Serpens Zoom into the Pillars of Creation and the smaller eagle that roosts there may reveal itself to you BINOCULARS Getting a closer look M16 is a famous object known as the Eagle Nebula and home of the ‘Pillars of Creation’, one of Hubble’s most iconic photographs. M16 is located approximately 2.5° west and slightly north of mag. +4.7 Gamma (a) Scuti, in a region of sky that looks ‘fuzzy’ due to it containing a number of deep-sky objects embedded within the Milky Way. Through binoculars, M16 appears like a small concentration of stars. These represent the cluster that lies at the heart of the nebula. The nebula itself is difficult to see, being easily lost to any sky brightening or light pollution. If you have access to larger than average binoculars – 11x80s or 15x70s – their increased magnification and aperture will give you a better chance.
SMALL TELESCOPE Get more detail A small telescope improves the view of the cluster but the nebula that gives M16 its eagle-like appearance can remain hard to detect. To do so, a dark and clear sky is needed, so wait until the Moon is out of the way. It’s worth keeping your eyes under dark conditions for 20 minutes to allow them to become properly dark adapted. Use a low power and take your time. A nebula or ultra-high-contrast filter can help. This is also a good target to practise the averted vision technique on: look slightly to the side of the faint object to get its light on a more sensitive part of your retina. The nebula is larger than the cluster and extends through it and down to the south. A dark, pointed intrusion appears to split the northern edge.
ISTOCK, PETE LAWRENCE X 3
LARGE TELESCOPE See it all A 250mm scope gathers enough light to start showing the expansion of the nebula to the south and east of the cluster. The expansion opens the nebula out to around 0.5° across, appearing like a faint background haze. For comparison, the embedded cluster appears approximately half this size, with about 30 stars visible through a 250mm instrument. Many describe the eagle from this view, its head in the cluster, body to the southeast and wings spread to the northeast and southwest of the body. The Pillars of Creation can be seen but require a 300mm or larger instrument. In photographs the Pillars form a second, smaller eagle, seen in profile and clutching a fish in its talons.
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October 2018
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October A trio of meteor showers pepper the skies with space rocks throughout the month
Key dates 4 OCTOBER This morning’s 29% waning crescent Moon is 3.3° from the Beehive Cluster, M44
9 OCTOBER Peak of the Draconid meteor shower
10 OCTOBER Peak of the Southern Taurid meteor shower under favourable conditions
21 OCTOBER Peak of the Orionid meteor shower under unfavourable Moon conditions
24 OCTOBER Uranus at opposition
WINNER SIR PATRICK MOORE PRIZE FOR BEST NEWCOMER
The Cone Nebula (NGC 2264) Jason Green (Gibraltar)
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Bright evening planet that appears to shrink through a telescope this month.
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Well positioned, reaching its highest point due south in darkness all month.
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October 2018
WorldMags.net October at a glance October’s a great time to explore the aquatic constellations
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he early evening sky is dominated by Pegasus, with the Great Square of Pegasus creating a large void among the stars. To the south and southeast of the Great Square is an ill-defined region of sky known informally as The Sea. It gets this name because it contains a number of waterrelated constellations. To the east, southeast and south of the Great Square sits Pisces, the Fish, most notable because of the Circlet located south of the Great Square. Southwest of Pisces lies Aquarius, the Water Bearer. Although generally brighter than Pisces, Aquarius is a large, sprawling and ill-defined constellation. The most prominent pattern here is the Water Jar, sometimes referred to by its more contemporary title: the Steering Wheel. Southwest of Aquarius is Capricornus, the Sea Goat. This is a very ancient constellation that resembles a southpointing triangle. If you struggle to see this, look for Mars, as the Red Planet is passing eastward through Capricornus. The watery theme continues southeast of Capricornus and south of Aquarius with Piscis Austrinus, the Southern Fish. The brightest star here is Fomalhaut, the most southerly first-magnitude star in the sky as seen from the UK. An easy way to locate Fomalhaut is to extend the line made by the western side of the Great Square of Pegasus south. If you do this, you’ll eventually arrive
Þ Both Northern and Southern Taurid meteor showers peak under favourable conditions. Both have a low ZHR of five meteors per hour, but have shown good fireball activity in the past at Fomalhaut, assuming it’s not hidden by a foreground object such as a house or tree!
Heroes and monsters South of Pisces is Cetus, the Whale/Sea Monster, another large and sprawling maritime constellation. This pattern is odd because its outline, as shown on star charts, looks like a whale with a tail to the northeast and nose to the west. But seeing it this way round, the brightest star in the supposed tail is orange Menkar, a name Distant Uranus reaches opposition on 24 October and should just be visible to the naked eye from a dark site
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that means ‘nostril’. The brightest star close to the whale’s supposed mouth is Deneb Kaitos, which means ‘whale’s tail’. So what initially looked like a west-facing whale is actually the wrong way round. Returning to the Great Square of Pegasus, a wedge-shaped pattern spreads out from its northeast corner. This is Andromeda, the Chained Princess. Just north of the middle of the wedge’s northern edge you’ll find the Andromeda Galaxy, M31. Its faint, elongated smudge is the furthest thing you can see with your just your eyes under normal conditions. It lies a staggering 2.5 million lightyears away. Andromeda stretches east towards her mythological husband, Perseus, the Greek Hero. Perseus contains the eclipsing binary star Algol, which appears to dim every two days, 20 hours and 49 minutes. In mythology the Gorgon Medusa had a stare capable of turning any living thing into stone. Perseus cut Medusa’s head off and revealed it to Cetus to save Andromeda, who had been chained to a rock as a sacrifice to the sea monster. Algol is supposed to represent the Gorgon’s eye and is also known as the winking demon. The ‘W’-shaped pattern to the north of Andromeda is Cassiopeia, the Seated Queen. She and her husband, king Cepheus, represented by a house-shaped pattern to the northeast of Cassiopeia, are Andromeda’s parents.
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November Comet 38P/Stephan-Oterma spends the month passing between Gemini and Cancer
Key dates 6 NOVEMBER A 2% waning crescent Moon sits 8.3° from Venus in the morning sky
8/9 NOVEMBER Ninth-magnitude comet 38P/StephanOterma sits just eight arcminutes from the Eskimo Nebula, NGC 2392
11 NOVEMBER A 16% waxing crescent Moon sits 42 arcminutes from Saturn in the early evening sky
17 NOVEMBER Peak of the Leonid meteor shower under favourable conditions
27 NOVEMBER This evening’s 73% waxing gibbous Moon lies 1.3° from the Beehive Cluster, M44
WINNER GALAXIES
0 6WDU 6WUHDPV DQG WKH 6XQƆRZHU *DOD[\ Oleg Bryzgalov (Ukraine)
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GLOBULAR CLUSTER PLANETARY NEBULA DIFFUSE NEBULOSITY DOUBLE STAR
VISIBLE PLANETS Where to spot the planets this month
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Mercury is poorly placed in the evening sky and unlikely to be seen.
Venus rapidly moves into the morning sky and by the end of November rises four hours before the Sun.
Evening planet Mars seems to shrink during the month, but also gains altitude when due south.
Jupiter is in conjunction with the Sun on 26 November and isn’t visible this month.
Losing altitude in the evening twilight, almost lost from view in the southwest at the end of the month.
Uranus is well positioned in the evening sky. At the end of November it sits between Aries and Pisces.
Well positioned evening planet. Mars approaches from the west towards the end of November.
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ASTEROID TRACK
ASTERISM MILKY WAY PLANET STAR BRIGHTNESS:
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WorldMags.net November at a glance The Crab Nebula crawls into view between the horns of Taurus
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navigational marker to the first entry in Charles Messier’s famous catalogue of deep-sky objects. Known as Messier 1 (M1), the Crab Nebula is the remnant of a star that was seen exploding as a supernova in 1054 AD. The star was seen by ancient astronomers as a ‘guest star’ in the night sky and was so bright that it could be seen in broad daylight for 23 days. A telescope is needed to see what’s left of it now. Head north of the Pleiades and you’ll find Perseus, the Greek Hero. The brightest star in Perseus is Mirphak, which has a lovely collection of stars nestled around it, some forming a distinct semi-circle around Mirphak itself. Perseus reaches towards his motherin-law from mythology, ‘W’-shaped Cassiopeia, the Seated Queen. Between them lies the famous Double Cluster, a physically close pair of open clusters that look spectacular through a low-power instrument, such as a pair of binoculars. Ninth-magnitude comet 38P/StephanOterma is well positioned in the early hours as it passes through the constellation of Gemini, the Twins. There’s a good photo opportunity on the nights of 8/9 and 9/10 November when the comet will be close to NGC 2392, the Eskimo Nebula.
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Þ Ninth-magnitude Comet 38P/Stephan-Oterma will be well placed during November and into December. The comet is brightest between 21–26 November at mag. +9.1 of a bull charging east. The Pleiades marks the bull’s shoulder blades while the ‘V’-shaped open cluster of stars known as the Hyades represents its face. The Hyades is also the closest open cluster to our Sun. Extend the arms of the Hyades east and you’ll eventually arrive at the two stars marking the tips of the bull’s horns. The southern star, Zeta (c) Tauri, is a useful
CANCER M44
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Clusters and comets South of Triangulum lies Aries, the Ram. The most distinctive pattern here is a bent line of three stars towards the west of the main constellation. Look east of this line and eventually you’ll arrive at one of the showpieces of the late-autumn sky: the Pleiades open cluster. This is also known as the Seven Sisters but if you have dark, clear skies and good eyesight it should be possible to see more than seven stars here. The Pleiades forms part of Taurus, the Bull, a sizeable pattern that only really makes sense when you realise it’s supposed to represent the horns, head and shoulders
10 Nov
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arly evening sees the stars of autumn fill the sky in the south and this is a great time to see the Andromeda Galaxy, M31. The core of this galaxy can be seen as an elongated smudge to the north of the middle of the wedge-shaped constellation of Andromeda, the Chained Princess. South of Andromeda lays small but distinct Triangulum, the Triangle. This constellation resembles a narrow isosceles triangle and in mythology was supposed to represent the shape of the island of Sicily. Located west and slightly north of the triangle’s apex is the Triangulum Galaxy, M33. It’s a tricky object to see through a telescope because it appears face on to us, a bit like a Catherine wheel. Consequently it has low surface brightness.
30 Nov
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71% waxing gibbous Sets at 01:20 UT (18 Nov) as the radiant is gaining altitude in the east
Þ A bright, waxing gibbous Moon sets as the Leonid radiant is gaining altitude in the east on the night of 17/18 November, leaving the early hours nice and dark to enjoy the show WWW.SKYATNIGHTMAGAZINE.COM
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5811(5ке83 AURORAE
In Autumn Dance Kamil Nureev (Russia)
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December 2018
WorldMags.net
December The end of the year sees meteors and comets streaking across the night skies
Key dates 7 DECEMBER Mars and Neptune appear just seven arcminutes apart this evening
13/14 DECEMBER Peak of the annual Geminid meteor shower under favourable conditions
16/17 DECEMBER Naked-eye comet 46P/Wirtanen passes very close to the Pleiades
21 DECEMBER Northern Hemisphere’s winter solstice
22 DECEMBER Peak of the Ursid meteor shower under unfavourable conditions
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CONSTELLATION NAME GALAXY
MOON PHASES Key stages in the monthly cycle FULL MOON 22 Dec
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GLOBULAR CLUSTER PLANETARY NEBULA DIFFUSE NEBULOSITY DOUBLE STAR
VISIBLE PLANETS Where to spot the planets this month
VARIABLE STAR THE MOON (SHOWING PHASE) COMET TRACK
VENUS
MARS
JUPITER
SATURN
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NEPTUNE
Morning planet well placed all month. Has a close encounter with Jupiter on the 21st.
Bright morning planet seen as a crescent through a telescope. Moon nearby on 3 and 4 December.
At its largest and brightest at the start of December. Close to Neptune on 6 and 7 December.
Morning planet slowly pulling away from the Sun. Close to Mercury on 21 and 22 December.
Just visible at the start of the month, low above the southwest horizon. Soon lost from view.
Well positioned evening planet. Slips over the border from Aries into Pisces on 3 December.
Well positioned evening planet at the start of the month. Near Mars on the evenings of 6th and 7th.
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PETE LAWRENCE X 3
ASTEROID TRACK
ASTERISM MILKY WAY PLANET STAR BRIGHTNESS:
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December 2018
WorldMags.net December at a glance Orion strides into view, bringing nebulae and clusters with him
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his month the Sun reaches its most southerly position in the M35 sky – the December solstice. 5 Dec This is a good thing too, as 10 Dec GEMINI Orion, the Hunter, is well placed this Geminid radiant month. His seven main stars stride across 13/14 Dec the December night sky like an old friend. 15 Dec The constellation contains many deepCastor sky riches, the most obvious of which sits 20 Dec in the centre of Orion’s sword, a pattern that appears to hang down from his belt. Any optical instrument, from small binoculars to the largest of telescopes, Pollux will confirm that this is the wonderful Orion Nebula, M42. Moon phase The nebula is a cloud of glowing gas and its brightest region, when seen through The Geminid meteor shower a small telescope, has a distinct kidney reaches its peak on 13/14 13 Dec shape. At the heart of the nebula sits December. After the Moon 34% wa xing crescent a small open cluster formed from the has set, this should be a Sets at 21:50 UT spectacular show nebula gas itself. The four brightest stars are very prominent and have led to this through Auriga, scattered along the path objects – M36, M37 and M38 – are worth being known as the Trapezium Cluster. of the Milky Way, which flows through It’s the light from these young, hot stars looking out for through binoculars or a the pentagon. In particular, three Messier telescope using a low-power eyepiece. that is exciting the gas in M42 and making Between Auriga and the it glow. Located northeast of Pole Star, Polaris, lies one of the Trapezium and separated LYNX 31 Dec the faintest constellations, the from the brightest area of M42 CASSIOPEIA ill-defined Camelopardalis. by a dark dust lane, is M43, a Comet CAMELOPARDALIS 46P/Wirtanen Its name comes from the fainter, comma-shaped nebula. 26 Dec ANDROMEDA ancient Greek words for A number of open clusters GEMINI Mirphak Capella camel and leopard, which and regions of nebulosity PERSEUS were combined to describe make up the sword. These are AURIGA the animal the constellation’s best seen through binoculars 21 Dec shape represents – a giraffe. or a telescope. Orion’s belt TRIANGULUM The last month of 2018 is also part of an open presents an exciting observing cluster known as Collinder opportunity to track a 70. Although it may not be 17 Dec Pleiades naked-eye comet. Comet 46P/ obvious to the naked eye, by Hamal ORION Hyades Aldebaran ARIES Wirtanen is expected to cross looking at the centre of the 16 Dec Betelgeuse the threshold into naked-eye belt you’re looking into the visibility during the middle of heart of this cluster. PISCES November and remain so until TAURUS the second week of January. Menkar At its brightest, the comet To the north of Orion lie the 11 Dec may reach third magnitude. two stars that represent the Rigel On the nights of 16/17 and tips of Taurus’s horns. The CETUS 17/18 December Comet 46P/ northern tip star is called Wirtanen will appear to pass Elnath and used to belong to 6 Dec ERIDANUS approximately 3° east of the Auriga, the Charioteer. Auriga Pleiades open cluster, giving lies further north and looks LEPUS astrophotographers an early like a misshapen pentagon 1 Dec Positions correct for 00:00 UT on shown date Christmas present as it does when viewed with Elnath so. On 18 December, the comet as part of the pattern. Þ Comet 46P/Wirtanen’s track up the sky during December. The comet is at its closest to Earth, just There are a number of should be visible to the naked eye all month, perhaps reaching third 11.6 million kilometres away. lovely open clusters aligned magnitude between 12–20 December.
Around Auriga
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Stats
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NAME AND CATALOGUE REFERENCE: Hyades, Melotte 25 CONSTELLATION: Taurus OBJECT TYPE: Open cluster VISUAL BRIGHTNESS: Mag. +0.5 (naked eye) DISTANCE: 153 lightyears APPARENT SIZE: 330 arcminutes PHYSICAL SIZE: Central core diameter 8.8 lightyears, outer envelope diameter 33 lightyears BEST TIME TO SEE: 15 Oct 03:00 UT, 15 Nov 01:00 UT, 15 Dec 23:00 UT
The orange star, Aldebaran, serves as the southern eye of Taurus even though it isn’t actually part of the Hyades cluster.
“The pointed tip of the V, marked by Gamma Tauri, represents the bull’s nose”
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L A N TS SO E A RG SE TA
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Hyades
Open cluster in Taurus Gaze into the eyes of the bull and he’ll lead you to the other stars that form the open cluster that lies closest to Earth NAKED EYE
The view from the ground
The Hyades is the V-shaped open cluster representing the face of Taurus. The cluster is bright, large and easy to find. Simply extend the line of Orion’s belt northwest to arrive at the orange star Aldebaran (Alpha (_) Tauri). This sits at the end of the southern arm of the V-shape. The rest of the V-shape is formed from four third-magnitude stars with other cluster members scattered around this structure. The Hyades is the closest open cluster to Earth, lying 153 lightyears away. Aldebaran isn’t part of the cluster being only 65 lightyears away. If you have keen eyesight, look halfway along the southern edge of the V where you should see two stars narrowly separated. This is the optical double star Theta-1 (e ) and Theta-2 (e ) Tauri.
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The Hyades
_
BINOCULARS Getting a closer look
ALAN DYER/VWPICS/ALAMY STOCK PHOTO, PETE LAWRENCE X 3
Binoculars are perfect for the Hyades. The longest arm of the V is a fraction over 4° in length, which fits into the field of view of a typical pair. The increased light gathering power of binoculars brings dozens of stars into view. The pointed tip of the V, marked by Hyadum I (Gamma (a) Tauri), represents the bull’s nose with Aldebaran his red southern eye. The star Ain (Epsilon (ÂĄ) Tauri) marks Taurus’s other eye, sometimes going by the name Oculus Borealis meaning ‘northern eye’. The two stars of Theta Tauri, on the V’s southern arm, separate well through binoculars. They’re about four lightyears apart – similar to the distance between the Sun and its nearest stellar neighbour – appearing close simply because of a line-of-sight alignment.
SMALL TELESCOPE Get more detail Where binoculars give a great view of the 5.5° core of the Hyades cluster, a telescope can often be too powerful to do it justice. If you fancy a challenge, bright Aldebaran has a faint mag. +13.6 companion located 31 arcseconds away in an east-southeast direction but it’s difficult to see because of the glare from Aldebaran. Although likely, it has not been confirmed that this is a true gravitational binary. Also look out for the mag. +6.4, open cluster NGC 1647 nearby. Imagining the Aldebaran-Ain as a mirror, reflecting the position of Hyadum I (Gamma (a) Tauri) points to NGC 1647’s location. Being 12 times further away than the Hyades, it’s interesting to see what a difference some distance makes!
The Hyades Ain NGC 1647 Hyadum I
Aldebaran
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You’ve seen the winners of 2017’s premiere astrophotography competition on the opening pages of our monthly guides and our favourite runner-up in December. Now see the rest of the runners-up and the highly commended entries
5811(56ƨ83 A runner-up prize was awarded for each main category except Robotic Scope and the Sir Patrick Moore prize for Best Newcomer
S GALAXIES NGC 7331 – The Deer Lick Group Bernard Miller, USA Equipment: $SRJHH $VSHQ &* 0 PRQR &&' FDPHUD 3ODQH:DYH &'. UHƆHFWRU 3DUDPRXQW 0( PRXQW
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Insight Astronomy Photographer of the Year
WorldMags.net
S OUR SUN Solar Limb Prominence and Sunspot Eric Toops, USA Equipment: Point Grey GS3-U3-60S6M CCD camera, homemade telescope.
S YOUNG ASTRONOMY PHOTOGRAPHER OF THE YEAR
S OUR MOON
Snake Moon
Jordi Delpeix Borrell, Spain Equipment: ZWO ASI174MM camera, Celestron C14 SchmidtCassegrain, Sky-Watcher NEQ6 Pro SynScan mount.
Kimberly Ochoa, USA – aged 14 Equipment: Canon EOS 700D camera, 250mm lens.
Evening in the Ptolemaeus Chain and Rupes Recta Region
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W STARS & NEBULAE One Stellar Day
Andras Papp, Hungary Equipment: Canon EOS 700D DSLR camera, SkyWatcher HEQ5 Pro SynScan mount, 18–135mm lens.
T SKYSCAPES Star Track in Kawakarpo Zhong Wu, China Equipment: Nikon D810 DSLR camera, 35mm lens.
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Insight Astronomy Photographer of the Year
WorldMags.net
S PLANETS, COMETS & ASTEROIDS
T PEOPLE & SPACE
Retrograde Mars and Saturn
The Cable Route of Half Dome at Night
Tunรง Tezel, Turkey
Kurt Lawson, USA
Equipment: Canon EOS 6D DSLR camera, 50mm lens.
Equipment: Sony Alpha 7R camera, 100mm lens.
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WorldMags.net HIGHLY COMMENDED Highly commended prizes were awarded for each main category, with three of the prizes awarded in the Young Astronomy Photographer of the Year category
S STARS & NEBULAE NGC 281 Pacman Andriy Borovkov, Ukraine Equipment: Moravian Instruments G2-8300 mono CCD camera, TS-Optics UNC 12-inch 1HZWRQLDQ UHƆHFWRU 6N\ :DWFKHU (4 3UR HTXDWRULDO PRXQW
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Insight Astronomy Photographer of the Year
1
WorldMags.net
YOUNG ASTRONOMY
PHOTOGRAPHER OF THE YEAR 1. Milky Way above Alpe di Siusi/Dolomites Fabian Dalpiaz, Italy – aged 15 Equipment: Canon EOS 5D Mark III DSLR camera, 50mm.
2. Rosa Mountain Andrea Imazio, Italy – aged 8 Equipment: Nikon D5500 DSLR camera, 18mm lens.
3. Orion’s Gaseous Nebula Sebastien Grech, UK – aged 13 Equipment: Canon EOS 60D DSLR camera, 6N\ :DWFKHU UHƆHFWRU 6N\ :DWFKHU EQ3 Pro mount.
2
3
W OUR SUN Ghostly Sun Michael Wilkinson, UK Equipment: ZWO ASI178MM CMOS camera, APM 3-inch refractor, Vixen Great Polaris mount.
S PLANETS, COMETS & ASTEROIDS Near Earth Object 164121 (2003 YT1) Derek Robson, UK Equipment: Canon EOS 1100D DSLR camera, 300mm lens.
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S PEOPLE & SPACE
T OUR MOON
Interstellar Travel
Mauna Kea Moonset
Fu Dingyan, China Equipment: Nikon D4S DSLR camera, 14-24mm lens.
Sean Goebel, USA Equipment: Canon EOS 7D Mark II DSLR camera, 1,000mm lens.
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Insight Astronomy Photographer of the Year
WorldMags.net
W GALAXIES NGC 4565 – Needle Galaxy
Andriy Borovkov, Ukraine Equipment: Moravian Instruments G2-8300 mono CCD camera, TS-Optics UNC 12-inch Newtonian UHƆHFWRU 6N\ Watcher EQ8 Pro equatorial mount.
SKYSCAPES X Nacreous Clouds Bartlomiej Jurecki, Poland Equipment: Nikon D800 DSLR camera, 300mm lens.
T AURORAE Aurora Shot from Plane Ziyi Ye, China Equipment: Canon EOS 6D DSLR camera, 20mm lens.
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Long-term imaging projects 2018
WorldMags.net RECOMMENDED
EQUIPMENT Suitable for any setup that can photograph stars. Best results will be obtained by using a colour camera such as a DSLR on a tracking mount.
Þ The diagram shows the relationship between a star’s magnitude and its effective temperature
&5($7( $ 3+272ƨ5($/,67,&
+(57=63581*ƨ RUSSELL DIAGRAM
PETE LAWRENCE X 7
Use your astrophotos to show how stars compare in terms of their light and heat. Pete Lawrence shows you how… he Hertzsrpung-Russell Diagram (HRD) is a fundamental way to show the relationship between a star’s absolute magnitude, or luminosity, and its temperature. The plot is very important in astronomy and astrophysics as it helps us understand how stars evolve over time. You can produce your own HRD in a very
T 100
straightforward manner by using graph paper with axes representing surface temperature and absolute magnitude. All you need to do to populate the graph is to access one of the multitudes of catalogues available online or via planetarium programs, extract the information for a particular star and plot it in the correct position.
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With 21st-century technology and the vast amount of star data available, a more efficient method would probably be to write some computer software to automate this process. However, in doing this, the wonder of discovery is somewhat side-stepped, because it’s only when you actually start to think about where each star goes, and realise that patterns do start to emerge, that the true meaning of the HRD becomes apparent. In order to liven the process up a bit, this project has a practical twist to it. What we’re asking you to do is take photographs of stars throughout the course of a year. They can be mainstream stars or obscure stars, but to keep things manageable at first, it is recommended to stick to brighter, named stars. Feel free to ignore this advice if you want – it’s ultimately your choice. For each star you photograph, it will be necessary to look up its effective temperature and its absolute magnitude. The absolute magnitude of a star is how bright it would appear if it were placed at a standard distance of 10 parsecs, or 32.6156 lightyears. This is something of a game changer for many stars in the night sky that may appear bright simply because they are fairly close to us. Consider Sirius, the brightest star in the night sky with an apparent magnitude of –1.5. If you placed it 10 parsecs away, it would shine at +1.5, fractionally brighter than Castor (Alpha (_) Geminorum) currently appears. The Sun fares pretty badly in absolute magnitude terms, shining at mag. +4.83 if 10 parsecs away. That’s a little brighter than the faintest star in the quadrilateral that forms the faint constellation of Equuleus, the Foal! By photographing the stars you observe on a regular basis, looking up their known values for temperature and absolute magnitude, and finally positioning them on a graph, you’ll gain a much deeper understanding of their nature and how they relate to each other.
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WorldMags.net STEP-BY-STEP GUIDE
Plot the stars’ positions on your Hertzsprung-Russell diagram
STEP 1
STEP 2
If you’re using a tracking mount, use a low-mid ISO and expose for multiple seconds. If you’re using a fixed tripod, use a mid-high ISO and keep the exposure relatively short to avoid trailing. Focus accurately using LiveView if available. The next steps will require you to create the HDR plotting area using a graphics editor.
Use a black background with axes labelled in white. Represent temperature by dividing the X axis into seven equal sections, labelled O, B, A, F, G, K and M. These describe stellar spectral classification and relate to a star’s temperature. O is the hottest, M is the coolest. There are others but the majority of stars you’ll image are covered by these seven.
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STEP 3
STEP 4
The Y axis should be divided into 30 equal rows and numbered from +20 at the bottom to –10 at the top. These divisions represent the star’s absolute magnitude (Mv), the lower the value, the brighter the star. Use a layer of thin grid lines to subdivide the graph for ease of placement.
Find the spectral classification and absolute magnitude for each star you photograph. A good starting point is the freeware planetarium program Cartes du Ciel (www.ap-i.net/skychart/en/start). Right click on a star and select the ‘about’ option. The spectral classification is shown as a letter followed by a number (ignore the Roman numerals).
MV Plx STEP 5
STEP 6
Absolute magnitude (Mv) isn’t given in the Cartes du Ciel ‘about’ data but can be calculated using the formula Mv = mv + 5*Log10(Plx/100), where mv = the visual magnitude and Plx = parallax in milli-arcseconds (mas). As an example, Mv for Sirius = –1.47 + 5*Log10(379.2/100) = 1.5.
Cut and paste your star image using a circular selection. Using the horizontal and vertical guides locate the star on the HRD grid. Each spectral class along the X axis is sub-divided into 10, starting from the right. Set the blend mode to lighten. Label the star either on the graphic or by naming its layer.
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Long-term imaging projects 2018 1 Stars of Aristillus (1W, 34N, colong. 5°) At certain illuminations much of the floor of Aristillus (55km) is in darkness with many peaks of its central mountain complex illuminated. Best time: morning terminator, one day after first quarter.
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2 Jewelled Handle (36W, 47N, colong. 30°) Illuminated arc of Montes Juras projected into the dark terminator shadow. Best time: morning terminator, three days after first quarter.
20 Cauchy’s Interrupted Western Shadow
18 Twin Spires of Messier
(48E, 2S, colong.130°) Impressive double-spike shadow from Messier Crater (12km x 9km). Best time: evening terminator, three days after full Moon.
21 Zeno Steps
23 Lunar V
(74E, 42N, colong. 105°) Stepped structure near libration-zone crater Zeno (65km). Best time: evening terminator, just after full Moon.
(1E, 8N, colong. 358°) Appearance of a large letter ‘V’ near crater Ukert (23km). Best time: morning terminator, first quarter Moon (appears at the same time as the Lunar X).
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3 1 4
27 Plato’s Ashen Light
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5
5 Gruithuisen’s Lunar City (8W, 6N, colong. 185°) Shows linear features radiating like lines on a leaf north from Schröter W (10km) Best time: evening terminator, one day after last quarter. It disappears fast!
23 20
6
15 18
7 10
11 16
9 8
14
7 Pearl Necklace
15 Nessie
(18W, 7S, colong. 17.1°) Beautiful curving arc of sunrise-illuminated peaks along 96km Fra Mauro’s western rim. Best time: morning terminator, one day after first quarter. Only visible for around one hour!
PETE LAWRENCE X 2
9 Hesiodus Sunrise Ray
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(9W, 52N, colong. 189.2°) Floor of Plato crater appears weakly lit when inside the terminator shadow. Possibly lit by reflected light from other bright features. Best time: sunset terminator, two days after last quarter.
17
6 Curtiss’s Cross (15W, 4S, colong. 193.3°) Difficult cruciform lighting effect near Fra Mauro H (6km). Best time: sunset terminator, last quarter.
(16W, 29S, colong. 19.3°) Impressive morning ray in Hesiodus. Best time: morning terminator, one day after first quarter.
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22
4 Star Tip Mountain
(23W, 28S, colong. 26.4°) ‘Bats’ ears’ appear to the west of the shadow cast by crater Kies A (16km). Best time: morning terminator, two days after first quarter.
26 Plato’s Hook (8W, 51N, colong. 15.6°) Plato crater (101km) rim peak shadow, which is supposed to appear curved. Best time: morning terminator, one day after first quarter.
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2
(11E, 43N, colong. 90°) Mountain in Montes Caucasus, which looks like a bright ‘L’. Best time: full Moon.
(8E, 71N, colong. 2.5° ) Shaft of light that appears to cross the floor of Barrow (93km). Best time: morning terminator effect, approximately six days after new Moon.
25 27
24 L-Shaped Mountain
25 Barrow Ray
19 O’Neill’s Bridge (50E, 15N, colong. 124°) Impression of an immense bridge between Promontorium Lavinium and Promontorium Olivium. Best time: evening terminator, three days after full Moon.
3 Cassini’s Moon Maiden
8 Kies A’s Interrupted Western Shadow
(40E, 14N, colong. 342.1°) Dotted beads of light along the western half of the rim of eroded crater Alexander (82km). Best time: morning terminator, approximately six days after new Moon.
(37E, 10N, colong. 328°) Central portion of 13km Cauchy’s shadow appears to be missing. Best time: morning terminator, five days after new Moon.
(34W, 41N, colong. 50°) Long-haired girl’s head and neck in profile formed by Promontorium Heraclides. Best time: morning terminator, four days after first quarter. Only works with an inverted (south-up) view.
(53W, 28N, colong. 52.8°) Solitary star-like point as the top of Mons Herodotus catches the morning Sun. Best time: morning terminator, four days after first quarter.
22 Alexander’s Beaded Rim
(1W, 8S, colong. 2.9°) Northeast rim of Ptolemaeus (154km) appears to mimic Nessie’s head and neck in profile. Best time: morning terminator, first quarter – better at low-res and suits poor seeing!
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10 Sword
13 Lunar 2
16 Larrieu’s Dam
(8W, 22S, colong. 181°) Rupes Recta (Straight Wall) forms the blade attached to the hilt of the unofficially named Stag’s Horn Mountains Best time: morning terminator, two days after first quarter.
(3W, 56S, colong. 182°) Thin, bright numeral ‘2’ formed from the rims of Deluc (48km) and Deluc D (27km). Best time: evening terminator, one day after last quarter.
(24E, 24S, colong. 343.7°) Linear scarp ‘wall’, which appears to contain a lake of dark shadow behind it. Best time: morning terminator, two days before first quarter.
14 Lunar Chi
17 Face in Albategnius
11 Lunar X (Werner X) (1E, 25S, colong. 358°) Best known clair-obscur effect, which produces a well defined letter ‘X’ due to partial lighting of the rims of La Caille (68km), Purbach (118km) and Blanchinus (68km). Best time: morning terminator, first quarter Moon.
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12 Eyes of Clavius (14W, 58S, colong. 15°) Rims of Clavius C (21km) and D (28km) at lunar dawn appear to look like eyes inside shadowed Clavius (225km). Best time: morning terminator, one day after first quarter.
(1W, 41S, colong. 358°) Greek letter Chi (r) formed by partially illuminated rims of Nasireddin (53km) and Stöfler J (76km). Best time: morning terminator first quarter – visible as the Lunar X is forming.
(6E, 11S, colong. 2°) Profile of a face caused by the shadow of the eastern rim of Albategnius (136km). Best time: morning terminator, first quarter.
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WorldMags.net 2%6(59,1* $1' 5(&25',1*
/81$5 &/$,5ƨ2%6&85 ())(&76 Pete Lawrence guides you through the strange sights created by the shadows passing across the Moon’s face dark shadow. It appears one-third up the he Moon is full of wondrous terminator from the southern limb at first detail that can be observed and imaged with modest equipment. quarter. At the same time as the ‘X’ forms, further north, another clair-obscur makes For this project we’re an appearance: the Lunar V. suggesting you create a gallery These effects are formed of lunar lighting effects. One by sunlight catching high of the fascinating aspects 5(&200(1'(' points on several lunar of lunar observing features. But there are is to watch how the other effects that are shadows play across Suitable for any setup that allows you to view and contained within one the Moon’s surface photograph the Moon. Best feature. Two good over the course imaging results will be examples are Plato’s of a lunar month. obtained by using a Hook and Plato’s Ashen Craters, mountains mono high-frameLight. The hook refers to and even flat, seemingly rate camera. the shadow cast on the floor uninteresting lava of the Plato crater by a peak on plains take on a whole new the southeast section of its rim. The appearance when the Sun’s light effect’s curved appearance is possibly due falls on them obliquely. to curvature in the crater floor. One interesting aspect to this is what’s Plato’s Ashen Light is a different effect known as a clair-obscur effect, a term that causes the floor of the crater to appear that comes from the French for light and milky when it should be dark. The most dark. An example of a clair-obscur effect is the Lunar X. When visible this looks like probable reason is reflections off other brightly lit nearby features. an illuminated letter ‘X’ floating against
T
EQUIPMENT
There are a lot of clair-obscur effects and some are more convincing than others. Some are serious effects that merit further scientific investigation, while some are simply fun targets to try and track down. To get you started, see the map opposite showing where a number of the more convincing ones are located. As well as an approximate lunar latitude and longitude position, we’ve also provided a colongitude value. Lunar colongitude is a value indicating the position of the morning terminator. This is approximately 270° at new Moon, 0° at first quarter, 90° at full Moon and 180° at last quarter. To plan your observations further we’d recommend downloading the excellent freeware Virtual Lunar Atlas (VLA) from www.ap-i.net/avl/en/start. This software will show the Moon’s colongitude in its ephemeris section and allow you to match date and times to achieve the correct value. Bear in mind that some of the effects may only last for an hour or two.
Þ Lunar clair-obscur effects, clockwise from top left: Twin Spires of Messier, the Sword, Plato’s Hook, Cassini’s Moon Maiden, the Lunar Chi and the Face in Albategnius
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Long-term imaging projects 2018
WorldMags.net
As Venus’s orbit takes it further away from the Sun, its crescent becomes finer
STEP-BY-STEP GUIDE Catch the subtle changes in Venus’s face over the course of the year
PETE LAWRENCE X 7
Image frame
STEP 1
STEP 2
Pointing away from the Sun, fit the full-aperture solar filter and remove, or cap, the finder. Fit the camera and IR pass filter. Centre the Sun’s disc and orientate your camera so that the Sun moves parallel to bottom of the frame when you’re slewing in RA. Focus as accurately as possible.
Using a planetarium program find the apparent Sun’s RA and Dec. coordinates. Unlock the mount’s setting circles and move them to match these values. Make sure you select the correct part of the setting circle. Check that the RA value increases as you slew east and Dec. increases as you tilt north.
STEP 3
STEP 4
Using a planetarium program find the apparent RA and Dec. of Venus. Adjust your telescope’s position so the setting circle readings match these coordinates. To double check, during the period March to May from the UK, the telescope should end up pointing to the left and up from the Sun.
Ensure you’re pointing away from the Sun and remove the full-aperture filter. Adjust the camera gain/exposure to give a bright, unsaturated sky. In the likely event that Venus isn’t visible, use a slow slew and carefully pan around the immediate area until you locate it. If you get lost, replace the filter and repeat the process from step 2.
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WARNING
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WorldMags.net Unless you are experienced at imaging planets close to the Sun we recommend restricting imaging dates to between 15 March and 17 October, recommencing after 5 November following inferior conjunction on 26 October.
on 17 August and this will present a problem. Where spring months are favourable for evening planets located in the west after sunset, late summer and autumn months are not. If you intend to image Venus in the evening sky after sunset, it’ll disappear before it enters the crescent phase. The rot starts to set in during late July, when Venus’s altitude declines rapidly after sunset. Being so low means the thick, turbulent atmosphere spoils the view as the planet’s light has to pass through it. By the end of September Venus sets with the Sun. The solution is to image Venus during the day. This gets easier with practice and gives you the opportunity to capture the Being on the far side of its orbit relative entire phase sequence. As Venus will be to Earth at the start of 2018, a telescope much higher in the sky, the view is often will show Venus to have a small steadier too. As ever, be aware 9-arcsecond disc, almost of the Sun and double check RECOMMENDED fully illuminated at the everything you do. Don’t end of January. Over put your equipment or subsequent evenings, your eyesight at risk. Telescope with 2,000mm or Venus gradually Before you know greater effective focal length edges further from it, you’ll be locating mounted on a polar-aligned the Sun, growing in Venus in the daytime equatorial mount, high-frame-rate apparent size slowly sky and imaging its FDPHUD ,5 SDVV ƅOWHU IXOO DSHUWXUH and showing an ever beautiful disc with ZKLWH OLJKW VRODU ƅOWHU decreasing phase. ease. This will give you mount with setting circles or In spring Venus a chance to put together Sun-enabled Go-To. appears high in the a fascinating record of sky after sunset. However, how its appearance changes greatest eastern elongation occurs throughout the year.
VENUSIAN PHASES Pete Lawrence shows you how to chart the changes in Venus’s crescent
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s we enter 2018, Venus is poorly positioned in the morning sky just west of the Sun. It reaches superior conjunction on 9 January after which it rapidly reappears in the evening sky. By the end of January it sets around 20 minutes after the Sun. It puts on a good evening appearance during subsequent months and this is a good time to dust off your planetary imaging skills. This project is simply to see how well, and for how long, you can image the planet’s disc. Although there is subtle detail to be had on Venus, the primary goal here will be to show the change in disc appearance throughout the year.
EQUIPMENT
STEP 5
STEP 6
It may take several attempts to locate Venus but once you have, adjust the camera gain/exposure to 70-80% saturation level. A low-mid gain with a high-frame rate is recommended. Make several 1,000+ frame captures for safety. Process the results using a registration-stacking program such as freeware AutoStakkert (www.autostakkert.com).
Compose your final image adding each result as a separate layer with blend mode set to lighten. Align the planet’s centre horizontally and give each result a date and time stamp. Inferior conjunction occurs on 26 October. Take care when removing the full-aperture filter close to this date, ensuring no sunlight passes directly down the telescope tube.
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+RZ WRť PDNH D FOLS RQ ƅQGHUVFRSH LOOXPLQDWRU 2018
WorldMags.net How to... MATERIALS TOOLS AND
0$.( $ &/,3ƨ21
ILLUMINATOR
Find bright targets more easily with 0DUN 3DUULVK’s red light illuminator The completed illuminator, fitted to a finder and ready for action
TOOLS Soldering iron, wire cutters/strippers, craft knife, steel rule, craft mat, hot-melt glue gun. MATERIALS Three mini LEDs, three resistors (3301), small quantity of thin wire, battery case (2x AA with a built-in on/off switch), flexible plastic sheet (an A4 stationary wallet or packaging). SUNDRIES Solder, electrical tape, hot glue sticks. FINISH Spray paint to match finder (optional).
could be reduced further, if required, by adding more resistors.
Easy wiring
f you’ve ever tried planetary imaging or high-powered visual observing, you will appreciate the importance of accuracy. To get a good image you need to precisely place your target within a very narrow field of view. But if the target is bright, such as a planet, for example, getting an accurate alignment upon it becomes difficult because its light can drown out the crosshairs in your finderscope. The solution to this problem is an illuminator. It’s a device that sits on a regular finderscope and makes its background glow red so that the crosshairs show up clearly against your target. The one we’re showing you how to make here requires no permanent modifications and can be adapted to suit an size of finder. To avoid the need for sourcing any tubing of any specific size, this design
ALL PICTURES: MARK PARRISH
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is built around a simple rolled-band and the judicious use of a hot-melt glue gun. In this example we’ll be using strips of plastic cut from a stationery folder, but you could also use any other clean plastic packaging material – just take care when cutting it, as you’ll need a sharp knife. If you are feeling ingenious you could adapt this aspect of the design to work with any other materials you have in your scrap box. The 1.8mm LEDs that provide the red light are glued to a band of thin plastic around the inside of the finderscope’s dew shield. This doesn’t greatly reduce the aperture, so it is not detrimental when locating bright objects. Protective resistors for each LED reduce the current to a suitable level and three LEDs produce a soft background glow. The light level
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You glue the resistors to a second band around the outside of the finderscope with a pair of wires leading back to a small battery and switch case. You may wish to locate your resistors closer to the battery case to reduce the overall size of the illuminator. This would require four wires between the case and the finder (one positive wire for each LED and one common negative), so some old telephone cable might suffice. Circuit diagrams for both variants are available to download from http://bit.ly/2iipyYn. Soldering is the most reliable and neatest joining technique, but you could use automotive-type crimp connectors as an alternative. The layout is quite straightforward but you must be sure to orient the LEDs correctly or they won’t work. The positive leg of each is only slightly longer than the negative, so identify each one before you begin bending things around! Solder a resistor to each positive leg then join the resistors together using short pieces of wire. Join one of these
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WorldMags.net Wire up your own red-light illuminator
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STEP-BY-STEP GUIDE
DAYTIME, BRIGHT TARGET
ILLUMINATION OFF, BRIGHT TARGET
STEP 1
STEP 2
Use a craft knife and a metal rule to cut some strips of thin flexible plastic approximately 12-15mm wide to make bands for the inside of your finder’s dew shield and around 20mm wide for the outside. We used red plastic to show up in the photos.
Test fit the inner band inside the finder’s dew shield and mark where it overlaps. Space the LEDs along it equally and use a hot-melt glue gun to stick them in place. Make sure the LEDs are all orientated the same way – the long leg is positive.
ILLUMINATION ON
Þ The illuminator creates a soft, red-sky glow that shows planets and crosshairs clearly
wires to the positive wire coming up from the battery case. Cover up the exposed ‘positive parts’ with insulating tape, then use short wires to join all the negative legs in a chain and finally link this chain to the negative wire of the battery case. We used plastic strips to cover the LEDs on the inside of the shield, and the resistors and wiring on the outside. Use glue to fill all the gaps between the components and to provide a diffusing layer over the LED lenses. Once the glue is set, the whole unit becomes rigid and robust enough to be slipped off and on again as required. We chose to add a ring of stiff card to tidy up the front and sprayed everything in black paint to match the finderscope. Velcro pads can be used to hold the battery case onto the side of your scope or mount when you’re not using the illuminator. Although the design is primarily for brighter targets, we found it helpful to flick the illumination on and off while aiming at fainter areas of sky for a reassuring confirmation of the crosshairs’ position.
STEP 3
STEP 4
Insert the first band and glue the overlapping join. Make a wider band to fit around the outside of the finder. Fold the positive legs of the LEDs over and solder each to a resistor. Glue each resistor to the outer band to keep them still while soldering.
Solder short pieces of insulated wire to join the free ends of the resistors in a chain. Solder a longer wire to link one end of this chain to the red output from the battery case. Fold over the negative LED legs create a chain, as above, then join one end to the case’s black output.
STEP 5
STEP 6
Insert batteries and check the circuit works. Add secondary inner and outer bands to cover all the elements and fill in the spaces between them with hot glue. Take care not to stick the illuminator to the finder. Add a diffusing layer of glue over the lenses of the LEDs.
You can add an optional ring to neaten up the outer end. We used thick card and painted the whole assembly with black spray paint to match the finder and offer some protection in damp conditions. A Velcro pad on the battery box holds it on the scope.
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How to… make an all-sky camera enclosure 2018
WorldMags.net How to... MATERIALS TOOLS AND
0$.( $1 $//ƨ6.< &$0(5$
ENCLOSURE
Steve Richards helps you protect your camera while you take timelapse images
COMPONENTS Clear 100mm acrylic dome with 20mm flange, IP56-rated PVC junction box (190x140x70mm), 32 SWG nichrome resistance wire (130cm length), two-way terminal block, 12V LED dimmer controller, two-core speaker cable, heat-shrink tubing. TOOLS Hand drill, 2mm and 4mm bits, 2-inch hole-cutter, Allen keys, crosshead screwdriver, 7mm metric spanner, small square file. SUNDRIES Sandpaper, black flocking material, silicone sealant, marker pen, masking tape, tape measure, bolts, washers and nuts. OPTIONAL Rubber feet, small dovetail bar, 22mm overflow pipe, pipe clips, pipe T connector and 1/4-20 bolt.
Þ Your biggest concern during construction is keeping the dome clean and scratch free
ALL PICTURES: STEVE RICHARDS
S
everal planetary imaging cameras now come packaged with wide-field lenses as well as standard ones. Providing you wrap the wide-field lens in a dew heater and can be sure of a rain-free night, they allow you to capture timelapses of the stars wheeling across the night sky. But if there is any risk of inclement weather then the camera and lens are at risk of damage. The solution is to protect them both with a waterproof enclosure, and that’s what this article shows you how to make. The versatile all-sky enclosure described here was built around our ZWO ASI 120MM planetary imaging camera, but the enclosure will accommodate a range of other models – all you need to do is construct a suitable mount for attaching
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your camera to the base. The design is also compatible with fish-eye lenses, should you want an even wider field of view. The domed section must be heated to keep dew at bay on both the lens and the inner and outer surfaces of the dome so this design includes a variable power heater that provides up to 6W of heat output. Start by printing out the dome template, which you can download from http://bit.ly/2z71hyu. Cut out and fix the template to the top of the enclosure – in this case an IP56-rated junction box – using masking tape. Drill a 2mm hole through the centre mark as a guide for cutting the 2-inch camera aperture. The dome must be handled carefully to avoid scratches; use a wad of clingfilm to protect it. Place the dome over the
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template, use masking tape to hold it in place. Carefully drill the six 4mm holes through the dome’s flange and the lid of the box. Place a 4mm bolt through each drilled hole in turn to ensure alignment. Remove the dome. In the lid, drill the seven 4mm holes needed for the heater element,
Þ The finished enclosure can be mounted on
a permanent post, like this, or a regular tripod
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STEP-BY-STEP GUIDE
Þ A single frame from a timelapse video recorded through the acrylic dome
then use a hole cutter to create the 2-inch hole in the centre. Cut a 110mm diameter piece of flock material and affix it over the hole in the lid to keep unwanted reflections to a minimum. Cut out the lens hole and the heater holes in the flock using a knife. Push a 130cm length of nichrome wire through the 1.6mm heat-shrink tubing leaving 10mm exposed at each end, then shrink the tubing. Make a circular heating element that just clips over the heater stand-offs by passing the wire through three pieces of 5mm heat-shrink four times and then shrink the outer tubing.
STEP 1
STEP 2
Attach the dome template downloaded from http://bit.ly/2z71hyu to the lid of the junction box. Drill a 2mm pilot hole through the centre mark. Place the dome accurately on top of the dome template and drill six 4mm holes through the dome’s flange and the box’s lid.
Remove the dome, then drill the seven 4mm holes for the heater element stand-off bolts and the wire exit point. Using the centre 2mm pilot hole drilled in Step 1 as a guide, use a 2-inch hole-cutter to cut out the hole for the lens.
Bolt it all together Attach the six M4x16mm bolts to the lid with a nut either side of the lid to form standoffs for the heater element. Clip the heating element over the stand-offs with the wire ends exiting through the seventh hole in the lid. Connect the heater element to one end of the speaker cable using a terminal block. Carefully apply a bead of clear silicon to the underneath of the dome flange and attach it to the lid using M4x20mm bolts, washers and nuts. Drill and file a hole in the box base so that the USB cable just fits though. Decide on your box mounting method – rubber feet for tabletop use, a dovetail bar with a 1/4-20 mounting hole for tripod use, or permanent installation using waste pipe and a 0.25-inch bolt through a pipe T piece – and attach the components to the base. Make a suitable mounting for your particular camera and lens combination and install the camera in the centre of the base. If you are using a ZWO ASI camera like ours, use the hole template included in the previously downloaded dome template and attach the camera with four spacers, nuts and washers. Attach the lid to the box base with the supplied screws, connect the speaker cable to the LED light dimmer and connect the dimmer to a 12V power source. You are now ready to capture some stunning wide-field vistas of the night sky.
STEP 3
STEP 4
Cut a 130cm length of nichrome wire and thread it through the 1.6mm heat-shrink tube and shrink it using a hair dryer or heat gun. Cut three 6cm lengths of 5mm-diameter heat-shrink tubing and thread the wire through them four times to form a circle.
Attach the M4x16mm heater stand-off bolts to the lid with nuts, washers and locknuts. Heatshrink the heater ring and clip it over the stand-offs. Push the wire ends through the seventh hole and connect them to the terminal block using the two-core speaker cable.
STEP 5
STEP 6
Run a bead of silicone around the underneath of the dome flange – do this as close to the middle of the flange as possible to ensure an accurate spread. Place the dome on the lid and affix it with the six M4x20mm bolts, washers and nuts.
Cut a rectangular hole in the base and push the USB and heater cables though. Drill suitable holes in the base and attach the rubber feet and dovetail bar, if required. Make a mounting for your camera and lens and mount them at the centre of the base to complete the project.
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+RZ WRť PDNH D VLPSOH VRODU ƅQGHU 2018
WorldMags.net How to... MATERIALS TOOLS AND
MAKE A SIMPLE
SOLAR FINDER Centre your scope on the Sun safely with Neil Wyatt’s straightforward add-on
MATERIALS 150mm length of plastic or aluminium tube, 25-32mm in diameter (ideally a good fit for your existing finder bracket); two bottle caps that fit the tube (or a pair of spare eyepiece caps); black and white plastic. TOOLS Junior hacksaw, craft knife, abrasive paper, dividers, scissors, glue.
Þ The finished finder alongside the milled
version – both look the part when mounted
Þ The biggest challenge is finding a suitable tube that fits snugly into your existing finder bracket
ALL PICTURES: NEIL WYATT
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lthough most astronomers observe the night sky, many also turn their attention to the closest star to Earth – the Sun. Inexpensive solar-film filters provide an affordable way to adapt small telescopes for solar observing and imaging, revealing sunspots and bright faculae. You will get an even better view if you invest in a Herschel wedge, while narrowband hydrogen-alpha and calcium-K filters enable you to see a greater range of solar features. But just as it isn’t safe to view the Sun through a telescope without a certified solar filter fitted, the same is true for much
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smaller finderscopes. Looking at the Sun through a finder will cause instant damage to your vision. How then, do you centre the Sun in your field of view? One way is to line the scope up so its shadow on the ground is as small as possible, but this isn’t very accurate, especially if you have your scope set up on grass. The most accurate way is to use a dedicated solar finder, a device that uses the ancient principle employed by pinhole cameras. Instead of using a lens, a small hole acts as an objective that projects an image of the Sun onto a screen at the far end of a tube. It is attached and adjusted in the same way as an ordinary finder, but
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instead of looking through a solar finder, you watch the screen on the finder’s rear and adjust the telescope until the image of the Sun is in the centre. The brightness of the Sun means that a hole less than 1mm across is sufficient. The resulting projection will be about 2mm across, and our screen about 150mm from the finder. Although the image is slightly enlarged, the light gathering power of the pinhole is puny – so it is completely safe.
How pro will you go? Our prototype finder was made by simply taping a piece of black plastic with a pinhole to one end of a metal tube and a white plastic screen to the other. This wasn’t very
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STEP-BY-STEP GUIDE
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Þ In use, the Sun is projected onto the white
disc; it’s aligned when it’s on the central dot
durable but proved the principle, allowing us to align a telescope with the Sun in a matter of seconds. Having access to a mill and a lathe, we then made a deluxe version using a black anodised tube from some bicycle forks with neatly knurled end-caps to hold the plastic discs in place at each end. You could, optionally, also mill a slot in the side of the tube so you can view the screen from either side. This finder worked so well we decided to dedicate a small achromat refractor to solar work by swapping out its regular finder for our solar one and semipermanently fitting a Baader solar filter to the telescope’s main lens. With a small, equatorial tripod it’s a great solar graband-go kit for those days when the Sun is only peeping out from behind the cloud for a few minutes at a time. The solar finder described in the Stepby-Step (right) does not require the machine shop – the tools you need are no more elaborate than a junior hacksaw and a craft knife. The end result may not be quite as pretty as the machined version (pictured left), but it works equally well as it has the same ‘high-tech’ optics. A lick of spray paint or even an offcut of carbonfibre wrap will easily make it look good enough to complement any solar scope. In use, you should swap it for the normal finder on your solar-filtered telescope (never, ever leave an optical finder on a solar setup). You may need to use some packing around your home-made finder if it is smaller in diameter than your finder bracket. Once you have your scope aligned with the Sun, just use the usual adjustment screws to centre our star on the screen, and that’s it. Whatever mount you have, manually tracking the Sun is now no more difficult than keeping it in the middle of the screen. Setting up the scope at the start of a session will now only take moments.
STEP 1
STEP 2
First cut the tube to length – 150mm is ideal. A ring of tape around the tube will help you ensure each end is cut square, as will holding the tube in a vice. Tidy the ends up with abrasive paper and roughen the surfaces in preparation for gluing.
Use dividers to scribe a disc of the same diameter as your tube on black plastic, although a compass and pencil will do an adequate job. Repeat this step with the white plastic. Make a clear centre mark on both of the discs.
STEP 3
STEP 4
Cut out the discs as neatly as you can. It pays to use small, sharp scissors, such as those you might use to cut your fingernails, as these will make it easier to follow the scribed line. With larger scissors you may have difficulty following the tight curve.
Take the black disc and use the dividers/ compass to make a neat hole of less than 1mm diameter exactly at the centre. Cut away any flash with a craft knife. Use a fine-tipped permanent marker to ‘dot’ the centre of the white disc.
STEP 5
STEP 6
Cut a neat circle out of the ends of your plastic bottle caps with a craft knife. This is a tricky task – you may find that lots of short nicks work better than trying to make a single cut. Use dividers to outline the cut if the cap hasn’t got a suitable marking.
Pop one disc in each of your end caps and then glue them in place. If you’re using two-part epoxy, make sure the adhesive fills the internal thread on the bottle caps so they stick to the tube well. Once the glue has set, your finder is ready to use.
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Observing for science 2018
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With the right contextual information, your observations could help advance our astronomical knowledge
Add a little extra info to your observations or images and they can EH LQFOXGHG LQ WKH VFLHQWLĆ&#x2026;F UHFRUG
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stronomy is unique among the sciences in that everyday people can contribute to the record. There are several professional organisations that accept amateur astronomersâ&#x20AC;&#x2122; images, as well as their sketches and reports of visual observations, and make them available for professional astronomers to use for research. On this page is a list of the main professional astronomical bodies that will accept your data, depending on what it relates to. Before submitting your images or observations, however, itâ&#x20AC;&#x2122;s worth reading and applying the general pointers regarding the preferred format for the data (below), so that professional astronomers can extract the most information from it. Itâ&#x20AC;&#x2122;s also worth checking each organisationâ&#x20AC;&#x2122;s website (bottom) for more specific guidance on how and what you can submit.
Make your images count for science 7R JLYH DQ\ LPDJH RU REVHUYDWLRQ VFLHQWLĆ&#x2026;F UHOHYDQFH DGG VRPH DGGLWLRQDO LQIRUPDWLRQ Date and time Write this in a format of YYYY-MM-DD and HH:MM:SS.S. For the time standard, use Coordinated Universal Time (UTC), which is the same as Universal Time (UT) or Greenwich Mean Time (GMT).
Orientation and scale Normally shown on an image or sketch by including a small icon to show the direction of north, south, east and west. This is especially important for objects that have no recognisable features, such as the Sun and narrow star fields.
Name and location These important details make it possible to scientifically compare work between observers and locations.
Equipment Typically the telescope or lens, eyepiece or camera and any filters you used to make the
observation. With cameras, note the settings, which can often be extracted from an image fileâ&#x20AC;&#x2122;s header with a suitable viewer. Observing conditions Include details of anything that may have affected the observations youâ&#x20AC;&#x2122;ve made, for example seeing or transparency, wind conditions, moisture in the air misting the optics and whether or not you, as the observer, were tired.
Where to send your observations
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These organisations accept amateur astronomersâ&#x20AC;&#x2122; images and observations, and collate them for use in professional astronomical research Association of Lunar and Planetary Observers (ALPO) International organisation maintaining sections that collect information on the Sun, Moon, planets, asteroids, meteors and comets. alpo-astronomy.org
International Astronomical Union, Minor Planet Center (MPC) The official organisation in charge of collating professional and amateur observations of asteroids and comets. www.minorplanetcenter.net/iau/mpc.html
International Meteor Organisation (IMO) US body set up in 1988 to support amateur meteor observers in disseminating and improving their work by collecting observations from around the world. www.imo.net
British Astronomical Association (BAA) The supporting body for amateur astronomers in the UK, with sections collecting observations on many areas of astronomy. www.britastro.org
International Comet Quarterly (ICQ) Circulates information and submission guidance on cometary observations; closely linked to the MPC. www.icq.eps.harvard.edu
Society for Popular Astronomy (SPA) National organisation for UK amateur astronomers; sections accept information on a wide spread of observational targets. www.popastro.com
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