2015 September Newsletter of Worthing Astronomers

The Southern Astronomer No.84 – September 2015

SOUTHERN ASTRONOMER THE

MONTHLY MAGAZINE OF WORTHING ASTRONOMERS & WORTHING SKYWATCHERS

Astronomy Meetings The groups listed below begin their meetings at 19.30hrs BST Worthing Astronomers (WA) meet on the first Friday of the month, every two months (February, April, June, August, October and December) at Goring Methodist Church Hall, Bury Drive (off of Aldsworth Avenue) Worthing, BN12 4XB. Admission £3.

Adur AS (AAS) meet at Southwick Christian Community Church, 1-5 Roman Crescent, Southwick BN42 4TY, first Monday of the month. Admission: £5 for guests, £3 for members.

WA and AAS venues have off road parking facilities and grounds adjacent for setting up telescopes when conditions allow.

More monthly details in the Quick View Diary (right).

Worthing Astronomers is a free to join society with a membership of about 400 persons, all united with an interest in Astronomy and its associated subjects.

With the aid of this newsletter, website, social media, regular star parties, workshops and public observing events we hope to encourage and share our interests in observing the sky with the public, our colleagues in our own group and with neighbouring societies.

This Issue Diary, listings, The Ones To Watch This Month1: Total Lunar Eclipse The Ones To Watch This Month 2 and 3 Report: Workshop Night - Telescope Clinic Planetary Cameras – The ZWO's Perseids 2015 Report Observing Notes for September

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QUICK VIEW ASTRO EVENTS DIARY September All times shown are Universal Time (UT = GMT = BST minus 1 hour) For WA and AAS details, see side bar on left

1 Sunrise 0515h : Sunset 1852h Neptune at opposition (03h) 4 Mercury at greatest eastern elongation; 27° (08h) Herstmonceux Science Festival Weekend start.

6 Herstmonceux Science Festival Weekend ends.

5 Occultation of Aldebaran by the Moon (05h) see page 3 Moon: Last Quarter (10h) 7 AAS: The Andromeda Galaxy, by Alan Drummond 12 Hants Astro - Starcamp 13 New Moon (06h) Hants Astro - Starcamp 14 Moon at apogee (11h) 19 WA: International Observe The Moon Night see page 3 20 WA: International Observe The Moon Night see page 3 21 Moon: First Quarter (09h) 23 Autumn Equinox (08h) 27 Sunrise 05.55h : Sunset 17.54h (6.55 a.m BST ; 06.54 p.m BST) 28 Full Moon – Total Eclipse (from UK) (03h) Moon at perigee (03h) 30 Sunrise 0600h : Sunset 1747h Mercury at inferior conjunction (15h)

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Lunar phases, September 2015

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cover page page 2-3 page 3 page 4 page 5 page 6 pages 7- 8

The Southern Astronomer No.84 – September 2015

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The Ones To Watch 1: Perigee Moon - Total Lunar Eclipse

he September Full Moon on the 28th will be the first total lunar eclipse to be seen in its entirety from the UK since 2007.

A lunar eclipse occurs when the Sun, Earth and Moon lay in a straight line relative to each other and this occurs at Full Moon. From the diagram at the bottom of the previous column it can be seen that the Sun throws the shadow of the Earth off into space.

Moonrise is at 17.34UT* on the evening of September 27 while the eclipse does not start until the early hours of the following morning.

Most months, the Moon misses the Earth's shadow but when the position of the Moons orbit is just right, the Moon will pass through that shadow – a lunar eclipse occurs. A little above or below and we will get partial or just a penumbral lunar eclipse.

The Moon will be in the south-west at the start of totality, in the constellation of Pisces. Photographically speaking, pictures of the eclipsed Moon can be aesthetically pleasing but also a good record of the event especially as metadata (camera type, speed, aperture, ISO etc.) with digital imaging is automatically recorded as well.

Progress of the Moon through the Earth's shadow

The Moon enters the Earth's outer shadow – the penumbra – at 00.11UT {1}.

This is known as first contact. Dimming of the Full Moon will be slow and subtle – it can look like a faint cloud covering the lunar face as the penumbral stage progresses.

The Moon enters the deep shadow – the umbra – at 01.06UT. Totality begins at 02.11UT. All going well, the Moon will go a coppery-red colour. This is the result of sunlight being scattered through the Earth's atmosphere and is known as the Rayleigh Scattering.

Lunar eclipse, March 2007

© Jan Halls

Capture the Moon With the availability of cameras so prolific it is a good time to think about capturing the eclipse with a camera.

Maximum eclipse is at 02.47UT with totality ending at 03.23UT. The Moon leaves the umbra at 04.27UT and finally leaves the penumbra at 05.22UT {7}.

Moonset is at 06.09UT.

Smartphone: If you intend to use a camera mounted on your smart phone you will need to connect it to a telescope; the image you will get using the phone by itself will be too small– you may also need to update your camera apps. The camera app that comes with your mobile phone is not really suitable for astrophotography but apps can be downloaded that give you more control of your camera – you will need to check out the Android or Apple app stores applicable to your handset. Hold the camera up to the eyepiece and take your exposures. This is called, afocal photography.

As you may see from the diagram above, the Moon does not pass centrally through the Earth's shadow. Depending on many factors, including the state of our planet's atmosphere, the Moon can sometimes take on a bright edge – the so-called, Christmas Pudding Effect. I don't think this likely due to the depth of pass by the Moon through the umbra but, it might be worth looking for (see picture, next column.)

DSLR: Like the old film-SLR's of old, these are now getting very popular with amateur astronomers. With one of these camera's there is quite a lot of control over speed, and if using in conjunction with a telephoto lens, aperture.

How Lunar Eclipses Are Caused

Unlike film of course, one can quickly view what has been photographed and adjust camera settings accordingly. Remember – the displayed image on the camera viewer may be brighter than how it appears on a monitor screen.

The above picture (taken close to mid-eclipse) was taken with a Canon 350 DSLR with a 250mm lens at f5, 2 second exposure with an ISO 800 speed setting.

Attach the camera to a telescope and more detail can be seen (top of opposite page).

This picture was taken with a Canon 300 attached to a 102mm refractor, ISO 200 and 1/125 exposure. The camera takes the place of the eyepiece. This is called prime focus imaging. An adaptor ring and/or T piece will be required to link camera and telescope together – these are available from astronomy stores or camera dealers.

Imaging with other cameras: If you have neither a smartphone or DSLR but have a telescope and regular 'point and shoot' type camera, interesting images can still be taken. These cameras have lenses that cannot be removed so the best way is to hold them up to an eyepiece of a telescope, adjust the telescopes focus and view the image on the rear screen of the camera – shoot away! *Do not forget to add an hour for British Summer Time.

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The Southern Astronomer No.84 – September 2015

Simulations via Stellarium Aldebaran occultation September 5 before (left) and after (right)

Penumbral aspect of March 2007 eclipse

On the morning of September 5 the waning Moon crosses in front of the bright star Aldebaran and the star will blink out only to reappear just as suddenly an hour and a quarter later. The egress of the star from behind the Moon may not be so visible as the Sun will be up. Times are (from Sompting): ingress at 04h 49m 52s UT; egress at 06h 07m 59s UT. West of Sompting the times will be a few seconds later; east of Sompting a few seconds earlier.

© Brian Halls

You will need to program the settings to manual to give better control over exposures. This is the same afocal photography as described under smartphones and is a simple but very effective way of recording bright images of the planets and the Moon.

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THE ONES TO WATCH 3: INTERNATIONAL OBSERVE THE MOON NIGHT

t does not seem all that long ago that we were preparing for the last InOMN evenings in 2014 and here we are with this years event coming around.

What ever method you decide on, have some dry runs if possible on the nights leading up to the eclipse so you can work out the best timings and methods for your own equipment.

The event is based upon the idea that astronomers around the world (both professional and amateur) throw open their telescopes to members of the public and share views of the Moon on a certain night.

What Will We See? Coinciding with the eclipse is the closest approach of the Moon to the Earth this year which makes it a perigee-Moon at 352 799 km (the expression super-moon has no astronomical meaning and may be misleading to the unwary.)

This year it is September 19 and 20 (that is, Saturday and Sunday). We have decided against the usual Friday event as the Moon will be setting early in the evening.

The Moon will be a day or so before first quarter and quite a few features will be visible. Though one or two lunar surface objects highlighted by the InOMN observing guide will not be visible to UK and European observers on the 19th they will be on the following evening.

The general view of the Moon will not change from any other time as the increase in angular diameter will not be measurable with anything less than very sophisticated equipment (now, prove me wrong!)

If observing the Moon with a pair of bins', telescope or through the telephoto lens, the subtle shadow changes will start to spread across the western portion of the face of the Moon. The change from penumbra to umbra will be also subtle until the whole Moon takes on a coppery-red colour.

The colour of the eclipsed Moon can never be guaranteed. Historically they can be very dark or extremely bright light orange. The French astronomer Andrè Danjon produced a table to describe the depth and colour of eclipses and is known as the Danjon Scale: L0: Very dark eclipse. Moon almost invisible, especially at mid-totality.

L1: Dark eclipse, grey or brownish in colouration. Details distinguishable only with difficulty.

L2: Deep red or rust-coloured eclipse. Very dark central shadow, while outer edge of umbra is relatively bright.

L3: Brick-red eclipse. Umbral shadow usually has a bright or yellow rim.

L4: Very bright copper-red or orange eclipse. Umbral shadow is bluish and has a very bright rim.

If you intend to look at the Moon through a small telescope or powerful binoculars you can also try and look at the surface of the Moon and see how the bright ray patterns and dark crater floors (like the crater Plato) change in their intensity.

All we need is to be sure of is the weather!

THE ONES TO WATCH 2: OCCULTATION OF ALDEBARAN Moon Map at 19.30UT September 19

Graphic by Occult 4

s the Moon slips across the sky it occasionally passes across stars (and some times a planet as it will do with Venus in April 2016); these are called occultations (from the Latin, to obscure).

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The dark lava plains or seas (mare) Crises, Fertility, Tranquility and Serenity will be visible during the evening.

During 2015, the star Aldebaran (α-Tauri) has been seen to pass behind the Moon on a few occasions - but this month we get to see the first one visible from the UK in the present sequence.

Crater features visible will be Messier and Messier A, crater chains such as the Catherina, Cyrillus and Theophilius triple crater 'chain' and three of the Apollo manned landing sites - Apollo 11 (Tranquility), Apollo 16 (Descartes) and Apollo 17 (Taurus Mountains). Plus, many, many more things. Hopefully a pair of fine nights to share with the public and our own members.

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The Southern Astronomer No.84 – September 2015 hobby of astrophotography.

WORKSHOP EVENING REPORT: August 7 TELESCOPE CLINIC

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ue to popular demand we ran a second Telescope Clinic (TC) evening for members.

Our first one in the spring was very popular and despite the fact this second one fell during the summer holiday season and many members could not get to it, it was a very interesting and well attended evening with over 40 members popping along with equipment and various items, with technical questions to problems and help.

Again, we were blessed with a fine evening so we could utilise the grounds of the Methodist Hall to set up telescopes.

A popular telescope on display was 'Daytime' Bob Leggett's 250mm FlexTube Dobsonian mounted instrument. Though the Dobsonian mount is a basic altazimuth, Bob's has been modified to a high degree (below).

Graham, Andy and Chris ponder a camera problem

©Steve Bassett

He was also able to demonstrate the various ancillary equipment available to the astrophotographer to help capture first class images each and every time.

Members get to have a look at Saturn

© Peter Wells

Bob got his nickname, 'Daytime' from his colleagues at the HantsAstro group for his enthusiasm for finding stars in daylight - he found both Vega and Polaris with his telescope while the sky was still bright during the TC evening.

Members got to view Saturn under the same bright sky conditions.

Bob Leggett (white shirt, centre) shows how his telescope works ©Steve Bassett

Necessity is the Mother of Invention, so goes the old saying. One of the problems for the travelling astronomer is the weight of equipment - one of the biggest culprits are the counterweights with which a telescope is balanced on an equatorial head. David Woods (who many of you will know), with a colleague has invented a solution to this problem, the CloverWeight.

Using cans of drink (either full of fluid or emptied of drink and filled with sand) can be fitted in place of the standard counterweight.

Once the trip is over, the sand is returned to the ground (or the drink supped up) and the cans disposed of in a proper and ethical fashion.

These weights are ideal for small 'scopes and will be a boon to those who may travel afar by not using up baggage allowance on air trips.

Several telescopes and binoculars were on hand for members to look at © Steve Bassett

A four can variant is also manufactured for larger instruments.

Many thanks once again to everyone who helped make the evening go well – those who bought equipment along, Chris Pennells who supplied the refreshments, Christa Sutton who helped with the serving and washing up of the cups and last but no means least, all those who attended.

Inside the venue, Chris Pennells was on hand to assist and advise members getting to grips with photographic equipment, especially those new to the

Our next Workshop is on October 2 at the same venue and will be about Making Every Photon Count, plus our AGM.

Details from DarkFrame Optics Ltd.

CloverWeight © David Woods

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The Southern Astronomer No.84 – September 2015 ZWO EARLY MODELS

The ZWO Planetary Cameras

by Zoltan Trenovski, MD at 365 Astronomy

The ASI120MC (one shot colour) and MM (monochrome) have been on the market for some time. They offer excellent value for money and are versatile cameras for imaging solar system objects. They support a wide range of resolutions enabling them to image the planets, moon and sun (with the correct filters in place for the sun).

The first 'planetary' cameras were converted web-cams – indeed many budget end planetary cameras (Celestron for example) basically still are. There has been a steady interest in recent years for more sophisticated kinds of cameras capable of shooting high frame rates. The article below introduces a popular type, the ZWO.

They connect to a laptop using a USB2 interface. They also have an autoguider port that enables them to be used as autoguiders for long exposure deep sky imaging and a 150 degrees wide-angle lens. These cameras are popular with Worthing Astronomer members for both planetary imaging and autoguiding. A number of images posted on the Worthing Skywatchers Facebook page are taken with these cameras.

INTRODUCTION

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lanetary imaging (including that of the moon and the sun) provides a good introduction to the art of astrophotography.

A simple mount and telescope is sufficient. The mount should preferably be GOTO or driven, with a long focal length telescope. Ideally an f-ratio (focal length of telescope divided by its aperture) of approximately 10 – 30 is required for planetary imaging.

NEW FAMILY MEMBERS

ZWO have shown their capability of keeping pace or even being in the forefront with technological development in CMOS cameras. The following cameras have only recently come on the market and offer the potential of A higher f-ratio can be achieved by using a Barlow lens, a Televue Powermate significant improvements in performance relative to older ZWO cameras. or similar.

ASI174 MC and MM In order to resolve planetary detail the best option is to take a video of the This camera is currently the top of the range of ZWO cameras. It comes in planet through the telescope. Specific CCD (or CMOS) cameras have been monochrome or colour, is USB3 compatible and has an autoguider port. The designed with astrophotography in mind. They are inserted into the diagonal highly advanced IMX174 sensor has Global Shutter technology as opposed to of the telescope in the same way as an eyepiece, although a threaded Rolling Shutter technology. This concerns how the sensor reads the signal connection is usually also possible. produced by each pixel and turns it into an image. In rolling shutter technology information from rows of pixels is gathered together and used to produce the A USB lead connects the camera to a laptop computer offering specifications image. Using information from rows of pixels can produce a back-log in required to support the camera. Specifically designed capture software shows information transfer and slow down the process. However, in Global shutter a live view image on the laptop’s screen. Sharpcap and Firecapture capture technology each pixel is read simultaneously. This minimises the potential for software are supplied with ZWO cameras on a CD or the latest versions can image distortion through motion blur during video capture that can be downloaded for free. Videos can be taken at different frame rates per compromise the final image. The IMX174 also maintains a very high frame second using controlled settings available in the capture software and rate, the highest of all the ASI cameras. Additionally, it has high sensitivity in processed using separate stacking software such as Registax 6 or low illumination, low noise and high contrast between light and dark areas Autostakkert 2 (both are free downloads). (high dynamic range). Its large sensor makes it suitable for the moon and the sun rather than planets. Similar to the ASI178 and ASI185 the use of ROI This software selects the best frames from the video and aligns and stacks (region of interest) can also yield good results for planetary imaging them to produce a final image. This can be processed further with other especially when a high focal ratio is achieved with larger telescopes. software, for example Photoshop, Lightroom or the open source GIMP. A wide range of cameras are available on the market, many of them designed to take a high number of frames per second and have powerful sensors. One family of such cameras is the ZWO ASI cameras that are based on CMOS sensors. ZWO ASI cameras range in price from approximately £100 to £500.

CMOS technology has been always cheaper than CCD technology and usually meant some compromise but recently this technology has gone through some incredible developments. Therefore, ZWO cameras now offer even higher value for money and this is especially true for their latest models, the ASI174, ASI178, ASI185 and ASI224.

A ZWO captures lunar features

© 365 Astronomy

The ASI178 is in a separate category with very large 6.4MPixel resolution and 14bit ADC. Although it has a small pixel size that might suggest that this camera is not as suitable for astronomy, a mode called “binning” can be used to combine pixels to achieve bigger pixel size although this does reduce resolution.

It offers the same technology as the ASI224 and 185 but takes it even further.

This is a very versatile camera with potential in various fields of application, including various types of astronomical imaging.

ASI 224MC and ASI 185MC These latest cameras are USB3 compatible, have an autoguider port and come with an all sky lens. The IMX 224 sensor offers Sony Exmoor and NIR technology. Exmoor technology improves picture quality under low illumination by incorporating wavelengths from the near infrared (NIR) part of the electromagnetic spectrum. Sony has also taken advantage of new technology to reduce the amount of noise typically inherent in CMOS sensors resulting in a very low readout noise and high Quantum Efficiency (QE). These two technological developments offer an increased quality of planetary image compared to older ASI cameras.

ZWO Camera (with lens)

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The Southern Astronomer No.84 – September 2015 ZWO Planetary Cameras

The ASI185 is practically the big brother of the ASI224.The difference is that it has a larger sensor. It also has a slightly higher readout noise (although still extremely low) and the same pixel size. The ASI224 is therefore better for planetary imaging whereas the ASI185 is better for the moon and sun.

Mars

© 365 Astronomy

The ASI185 would still be suitable for planetary imaging with larger telescopes with a long focal length. An alternative is to take advantage of the ROI feature that uses only part of

the sensor of the ASI185 to capture a portion of the image of the planet.

CONCLUSION © Andy Li

The ZWO family of planetary imaging cameras offers a wide range to meet the different interests and budgets of club members. The relatively low budget ASI0134 still offers the potential of good images showing significant detail on solar system objects. The new ASI224 offers a higher budget and versatile powerful planetary imager that we believe is set to become a best seller in its price range. Finally, the outstanding ASI174 offers the potential for stunning images of the moon and sun but at an increased cost. None of these new developments should take anything away from the original ASI120 offering an excellent value planetary imager with an autoguider port and an all sky lens.

The sky is literally the limit!

365 Astronomy is a UK distributor for ZWO cameras and accessories. All of these cameras are available from 365 Astronomy and other ZWO dealers across the country.

365 will have a stand at the Herstmonceux Astronomy Festival on 4-6 September from 106 Saturday and Sunday and will be offering a 10% discount on all ZWO products at this festival.

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PERSEIDS 2015 REPORT

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he annual Perseid Meteor Shower made its appearance in Mid-August and despite the overall cloudy conditions, members were able to observe (and capture images) of natures own firework display.

This year was predicted to be good conditions; the Moon was a day or two from being new and was thus only a small crescent in the morning sky so its light would not interfere with meteor seeing. It was all really down to the weather conditions. Cloud cover over Britain was mixed as it was over our skies here in the south.

This did not however deter our members of WA or Skywatchers from going out and looking for meteors. Here are some of the pictures they took.

From Ferring sea front

© Andy Li

Next year, the Perseid meteors occur with a young moon in the sky during the early part of the evening, so again seeing conditions may improve. Maximum is expected during the early afternoon of August 12 so the night of 11/12 and 12/13 could give good results.

As this 2016 period falls at the weekend, it might be a great chance for us to get together; though that's next year it is something for us to have a think about now!

Perseid and the Milky Way

© Scott Prideux

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The Southern Astronomer No.84 – September 2015

OBSERVING NOTES September All times are expressed as Universal (UT) and can be considered the same as GMT (BST minus 1 hour).

Information below, and all sky-map on page 8, is for the 15th of the month unless stated otherwise.

Meteorologist refer to the first of September as the first day of Autumn. For everyone else however that point starts on September 23 when the Equinox occurs at 08.21UT when the plane of the Earth's Equator passes the centre of the Sun. From this point onwards, the north pole of the Earth tilts away from the Sun while the southern tilts towards it.

Winter nights are on their way.

Visibility of the planets mid-September

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ercury makes a brief appearance in the evening sky this month setting a little after the Sun however it is poorly placed for observation coming to inferior conjunction (Mercury lays between us and the Sun) at the end of the September.

Venus is due east at 04.00UT mid month, low in the pre-dawn sky at about 15° and -4.8m, so bright!

In the telescope (or even a good pair of binoculars) the planet will look like a large crescent – angular diameter 42” arc-seconds - with a 20% phase which will gradually increase while, the angular diameter slowly decreases. If possible, try and track the planet as the sky gets brighter, glare from the bright cloud covered world decreases and detail in the phase and even cloud has been known to be observed. If you cannot do this, a blue (W80B) filter will help.

Both Mars and Jupiter are not too far behind either though rising in the twilight; all three planets are well placed for (early) observing at about 05.00UT.

The Western Veil Nebula

© Steve Bassett

Saturn is the only bright planet in the evening sky, low in the south-west as dusk falls. Outer planets Uranus and Neptune are star like objects – a sizeable telescope is required to make out their disks – are also low in the southern sky though should be able to be seen on the InOMN evenings on the seafront.

Further south from Cygnus is the triangular constellation of Scutum. In Scutum is another kind of deep-sky object – an open cluster – M11 or the Wild Duck Cluster, so called because of its brighter stars resemblance to a flock of birds rising to flight. Personally I cannot visualise the 'birds' but, it is a beautiful sight to see however. At about 6m the cluster contains it is believed, in the region of 3000 stars.

Uranus rises almost due east at 18.41UT while Neptune is south-east at the same time. Both objects will be visible during the night.

Low in the south – so a good horizon is best – is the Lagoon Nebula (M8) and the Trifid Nebula (M20), both in Sagittarius.

The Perseid Meteors are now passed and we must wait until later in the year for the next prominent shower. There are no predicted comets brighter than 10m until the end of the year.

When seen with the eye through a telescope they take on a hazy cloud like patch but when imaged they show colouration.

Stellar &Deep Sky During the mid evenings in the latter part of summer and early autumn, the Milky Way (our very own galaxy) lays overhead, stretching from the north-east to the south-west.

It is in this region that many deep sky and stellar wonders can be observed, even with a small telescope on occasion as these celestial objects are our own 'next-door' neighbours in the universe. Too many to name and describe in the short space available, we'll have a brief look at some of the prominent ones – amazing to the new sky-watcher and old-hand, alike.

Overhead (as in the sky chart on the next page) is Cygnus. This constellation lays in the Milky Way and a look through a pair of binoculars or a small widefield eyepiece telescope will show many faint stars. Of course from our lightpolluted skies we get to see only the brighter stars but, the constellation contains many deep sky wonders. One such is the Veil Nebula.

Though 7m it is a very faint object and was discovered by Sir William Herschel on September 5, 1784. It is actually part of a much larger area subsequently revealed by photography that is called, the Cygnus Loop. The Loop and its visible portion shown so very well in Steve Bassett's image taken in August and shown atop of the next column, is the remnants of a supernova that detonated, it is calculated, between 5000 to 8000 years ago. The bright star in the picture is the line of sight star, 52-Cygni.

The Trifid Nebula

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© Hunter Wilson

The Southern Astronomer No.84 – September 2015

The Night Sky from Worthing at or around 21.30UT mid-month

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