MAC August 2011 Magazine by MAC Realta

Midlands Astronomy Club Magazine

Sky Guide - Beginner’s targets for August In August, we have one of the best meteor showers of the year for the naked eye. The Perseids should offer their best viewing in the evening hours of the 12th of the month and peak on the 13th. The shower will appear to radiate from the Northeast from the constellation of Perseus.

Also in the same area is a much dimmer globular cluster, M28. M28 is located just above the top star of the teapot (Kaus Borealis). It will provide a nice comparison with the much closer M22. M28 contains about 100,000 stars and is located approximately 15,000 light years from us.

Telescopic Sights We'll concentrate our August tour in the constellation Sagittarius. Find the teapot asterism (or house) in the South and you're there. Sagittarius is home to dozens of wonderful sights and is a great place to just scan with your telescope as you'll pick up dozens of open and globular clusters. When you look toward Sagittarius you're looking toward the centre of the Milky Way.

The Lagoon Nebula (M8) is located just above the teapot and presents a wonderful example of an emission nebula. To locate it, use the star in the top of the handle (Nunki) of the teapot and the star at the top of the teapot (Kaus Borealis). Follow this line the same distance out from the teapot and you're there. The Lagoon Neb is quite large so use a low to medium powered eyepiece to get the most out of the view. Embedded within the nebula is an Open Cluster, NGC6530. The Nebula is a cloud of ionized hydrogen gas approximately 50 light years in diameter located approximately 5000 light years from us.

M22 is one of the best globular clusters for Northern Hemisphere observers. To locate M22, use the top of the teapot (Kaus Borealis) and the top star of the handle of the teapot (Nunki). M22 forms the corner of an "L" with these 2 stars. M22 consists of approximately 500,000 stars located 10,000 light years away.

To help find your way around the night sky, Skymaps.com makes available for free each month. The Evening Sky Map is suitable for all stargazers including newcomers to astronomy and will help you to: • identify planets, stars and major constellations. • find sparkling star clusters, wispy nebulae & distant galaxies. • locate and follow bright comets across the sky. • learn about the night sky and astronomy.

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Just North of the Lagoon Nebula (about a low powered eyepiece field's width) is another fine Nebula, the Trifid (M20). The trifid is much smaller than the lagoon and will require dark skies to get a good view. The trifid is also a cloud of Ionized gas approximately 25 light years in diameter which is located about 2500 light years from us. Embedded within the nebula is a multiple star system, HN 40. Small scopes will show it as a double star while a 6" - 8" scope will show an additional 2 members. Just outside of the eyepiece view to the Northeast is the Open Cluster, M21. This is a loose aggregation of about 50 stars of which a dozen or so are visible in small scopes. M21 is also located about 2500 light years away. One of the brightest Nebulae in the sky is the Swan Nebula (M17), also located in Sagittarius. Using the depth of the teapot as a gauge, go up (North) from the top of the

Issue 25- August, 2011

M22 (NGC 6656) is one of the brightest globulars that is visible in the night sky and is located about 10,600 light-years away. M17 (NGC 6618 or Omega Nebula) was discovered in 1745. Earth's distance to the Omega Nebula is between 5,000 and 6,000 light-years. M8 (NGC 6523 or Lagoon Nebula) is a giant interstellar cloud, classified as an emission nebula and is located at an estimated distance of 4,100 light-years from Earth. teapot about 1 and a half times this distance toward the constellation Scutum. Scutum contains several 4th magnitude stars which form a diamond shape. The lower star of the "diamond" also points right at M17. M17 appears as a check-mark shape in the scope and provides a fascinating view. The nebula is located about 5000 light years away from us.

These are just a sampling of the many gems located in this area of the sky. A good star chart will point you to many more in this area. The Planets Jupiter and Saturn are up early in the morning hours. Well, that's about it for the month.

By Kevin Daly http://members.aol.com/kdaly10475/index.html

Club Notes Next Meeting: The next MAC meeting will be on the 6th September at 8pm in the Presbyterian Church and Hall, Main Street, Tullamore. ______________________________________ Club Observing: Perseids StarBQ Sometimes we get lucky, other times the weather hampers our efforts. Nonetheless, you are still invited to our StarBQ. Come along, bring some food and implements for a barbecue, sit around the campfire under the stars and retire to your own tent for the night! We are planning for Friday 5th first with a fallback to the 6th should the weather prove nasty for us. If it's cloudy, we'll still go ahead - purely for fun! - FREE EVENT

Latest Astronomy and Space News Kids Astronomy Quizzes and Games Monthly Sky Guide Internet Highlights

Midlands Astronomy Club Magazine

Bucket List Object #7: The Green Flash ................................ 9

Kids Section Kids Korner ....................................................................... 10 Front cover image: For the last time, the US Space Shuttle Atlantis approached the International Space Station (ISS). Following a dramatic launch from Cape Canaveral last week that was witnessed by an estimated one million people, Space Shuttle Atlantis on STS-135 lifted a small crew to the orbiting station. This picture shows Atlantis rising toward the ISS with its cargo bay doors open and over 200 kilometres below lie the cool blue waters of planet Earth.

Credit & Copyright: ISS Expedition 28 Crew and NASA

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Quizzes and Games Exercise your brain ............................................................ 11

Monthly Sky Guide Beginners sky guide for April .............................................. 12

Internet Highlights Special content only available with the online version of the magazine ................................................................ 13

4. Except for the recently discovered moons far out in the solar system, almost all moons have had names for many years. One planet has a moon with no other official name, which one is it?

Pluto Venus Earth Mars 5. The first four moons beyond our own were discovered in 1610. Which planet's moons were they?

Jupiter Uranus Saturn Neptune

Earth Mercury Mars Venus 9. Which moon was visited by a space probe in 2005?

Enceladus Tethys Titan Dione 10.Most moons have their own orbits, relatively far away from any other moons. These two moons are in almost the same orbit, close to Saturn's rings. Who are they?

Ananke and Metis Janus and Epimetheus Belinda and Ariel Despina and Nereid

8 5 9

6 1

9 5

6 7

3 9

Check your answers

moons. Cordelia, Ophelia, Bianca, Cressida, Desdemona, Juliet, Portia, Rosalind, Puck, Miranda, Caliban, and Sycorax are all Shakespearean names.

Getting Started - The Plough as an Observing Aid ................. 8

8. Which of the inner four rocky planets has the most moons?

Answer 1: The correct answer was Ganymede which is one of Jupiter's moons, is not only the largest moon with a diameter of 3,280 miles, or 5,262 km, but it's bigger than two planets, Mercury and Pluto.

Perseid meteor shower ........................................................ 7

Ida Ceres Asteroid B-612 Hermione

Titania Oberon Triton Umbriel

Answer 7: The correct answer was Triton. Triton, which looks like a cantaloupe, orbits Neptune in a retrograde orbit, the only large satellite to do so. This means it orbits opposite to the rotation of the planet.

Happy anniversary, Neptune! ............................................... 6

3. Which asteroid was the first found to have a satellite orbiting it?

7. M o o n s that are geologically active are among the most interesting. Which moon is known for its giant ice geysers?

Answer 2: The correct answer was Io. Io, another one of Jupiter's moons, was first photographed during the Voyager 1 and 2 flybys in 1979. Scientists were pleasantly surprised to see the sulphur eruptions.

Saturn Agonistes --1.5-Billion square-mile storm as wide as Earth .............................................................................. 5

Sinope Rhea Iapetus Io

Answer 8: The correct answer was Mars. Mars has two moons, Phobos and Deimos. They are named for the attendants of the Roman war god Mars, their names mean fear and panic. Mercury and Venus have no moons.

"Soccer Ball" Nebula discovered by amateur astronomer........ 5

2. Which moon was the first to be discovered to have active volcanoes?

Answer 3: The correct answer was Ida. Dactyl was discovered to be orbiting Ida by Galileo in August 1993 as it flew through the asteroid belt on its way to Jupiter. There are 9 asteroids known to have satellites, the most recently discovered was Hermione.

You can see more about the club and its events on www.midlandsastronomy.com or contact the club via e-mail at midlandsastronomy@gmail.com Meetings are informal and are aimed at a level to suit all ages.

Ganymede - The only moon in the solar system with its own magnetic field.......................................................... 4

Uranus Neptune Jupiter Saturn

Answer 9: The correct answer was Titan. The Cassini mission arrived at Saturn in July 2004. It released the Huygens probe several months later which landed on Titan, Saturn's largest moon.

New moon discovered orbiting Pluto ..................................... 4

Titan Ganymede Charon Europa

SUDOKU

Answer 4: The correct answer was Earth. Our moon has no official name other than "Moon". Some people have suggested names, one of the most popular is Luna.

Black Hole hosts Universe's most massive water cloud ........... 3

6. Most moons are named for mythical characters. Which planet has moons named for characters from several different Shakespeare plays?

Answer 10: The correct answer was Janus and Epimetheus. Despite their odd orbits, these two icy moons never come closer to each other than 13,000 miles or 21,000 km apart.

NASA's WISE finds Earth's first Trojan Asteroid ..................... 3

1. Which moon is the largest moon in the solar system?

Answer 5: The correct answer was Jupiter. Ganymede, Io, Callisto, and Europa were discovered by Galileo Galilei.

Latest Astronomy and Space News

All are welcome to attend. It also holds infrequent Observing Nights at its Observing Site in Clonminch, or at a memberâ&#x20AC;&#x2122;s house (weather permitting) on the first Friday of every month..

Exercise your brain

contents

Answer 6: The correct answer was Uranus which has at least twenty

MAC meets on the first Tuesday of the month in the Presbyterian Hall, High Street, Tullamore from 8pm.

Midlands Astronomy Club Magazine

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Midlands Astronomy Club Magazine

Kid’s Korner A cool Sun for cool music? We learn about the world by slicing it up into smaller pieces. We study history, geography, math, art, music, science, and lots of other subjects. But to really understand our world, we must reconnect the pieces to see how they all work together.

Midlands Astronomy Club Magazine Sunspots are areas of particularly strong magnetic forces on the Sun's surface. They appear darker than their surroundings because they are cooler. Even so, scientists have discovered that when there are lots of sunspots, the Sun is actually putting out MORE energy than when there are fewer sunspots. Sunspot activity occurs in cycles of about 11 years. But during about 1645 to 1715, hardly any sunspots

Above: Through special DARK filters, sunspots may look like the picture on the left. The sunspot groups are as big as the giant planet Jupiter! On the right is a closeup of some other sunspots. The larger sunspot on the right is bigger than Earth!

This is a story about connections. This is a story were seen! From the time sunspot Why so cold? about how But why did Europe get so much records were first kept until now, events on the colder than normal during these such a "solar rest period" has not Sun 300 Above: Each year of this Douglas years? Only recently did scientists been seen. It was during this y e a r s Fir tree's life, a new ring of growth make the connection and figure out period that Europe experienced the ago may was added. "Little Ice Age." It was during this the most likely answer. h a v e time that Stradivari came along and affected some of the Violins are made from wood. The Astronomers have been studying made possibly the best violins ever beautiful music we best violins are made from very the Sun for hundreds of years. from the slow-growing trees of his hard, dense wood. The best wood Using very special dark filters and chilly era. still hear today. comes from trees that have grown lenses, they have studied the most In the 17th century very slowly, laying down a thin ring obvious feature on the Sun: (1644 to 1737) of dense new growth each year. Sunspots. lived a violin Long winters and cool summers maker n a m e d make for slow tree growth. Antonio Stradivari. His workshop During about 1560was in Cremona, Italy. He made 1850, which included hundreds of violins, many of the time Stradivari which are still played today. made his violins, Europe They are prized for their rich (including Italy) and beautiful sound, especially in experienced a "Little Ice the hands of master violinists. Age." It was so cold that normally freeNo one has since been able flowing rivers and to make a violin that sounds canals froze over. quite like a Stradivarius (a violin made by Stradivari). Stradivari used the Just how did Stradivari make hard, dense wood such wonderful violins? No from the spruce one knows for sure, but one trees growing Above: This picture is of made of three overlapping photos. It shows the rings in the new idea makes a lot of " essiah."The first row during this time spruce tree used to make the most famous Stradivarius violin, the M sense. in a nearby forest of numbers gives the width of each ring in millimetres (one mm is about the thickness of a fingernail). The bottom row gives the years in which each ring grew. to make his violins.

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NASA's WISE finds Earth's first Trojan Asteroid Astronomers studying observations taken by NASA's Wide-field Infrared Survey Explorer (WISE) mission have discovered the first known "Trojan" asteroid orbiting the sun along with Earth. Trojans are asteroids that share an orbit with a planet near stable points in front of or behind the planet. Because they constantly lead or follow in the same orbit as the planet, they never can collide with it. In our solar system, Trojans also share orbits with Neptune, Mars and Jupiter. Two of Saturn's moons share orbits with Trojans. Scientists had predicted Earth should have Trojans, but they have been difficult to find because they are relatively small and appear near the sun from Earth's point of view. "These asteroids dwell mostly in the daylight, making them very hard to see," said Martin Connors of Athabasca University in Canada, lead author of a new paper on the discovery in the July 28 issue of the journal Nature. "But we finally found one, because the object has an unusual orbit that takes it farther away from the sun than what is typical for Trojans. WISE was a game-changer, giving us a point of view difficult to have at Earth's surface."

The WISE telescope scanned the entire sky in infrared light from January 2010 to February 2011. Connors and his team began their search for an Earth Trojan using data from NEOWISE, an addition to the WISE mission that focused in part on near-Earth objects, or NEOs, such as asteroids and comets. NEOs are bodies that pass within 28 million miles (45 million kilometres) of Earth's path around the sun. The NEOWISE project observed more than 155,000 asteroids in the main belt between Mars and Jupiter, and more than 500 NEOs, discovering 132 that were previously unknown. The team's hunt resulted in two Trojan candidates. One called 2010 TK7 was confirmed as an Earth Trojan after follow-up observations with the Canada-France-Hawaii Telescope on Mauna Kea in Hawaii. The asteroid (300 meters) unusual orbit motion near

is roughly 1,000 feet in diameter. It has an that traces a complex a stable point in the

Black Hole hosts Universe's most massive water cloud In a galaxy 12 billion light-years away resides the most distant and most massive cloud of water yet seen in the universe, astronomers say. Weighing in at 40 billion times the mass of Earth, the giant cloud of mist swaddles a type of actively feeding supermassive black hole known as a quasar. Among the brightest and most energetic objects in the universe, quasars are black holes at the centres of galaxies that are gravitationally consuming surrounding disks of material while burping back out powerful energy jets.

"As this disk of material is consumed by the central black hole, it releases energy in the form of xray and infrared radiation, which in turn can heat the surrounding material, resulting in the observed water vapor," said study co-author Eric Murphy, an astronomer with the Carnegie Observatories in Pasadena, California. The vapour around this particular quasar represents enough water "to fill all the oceans on the Earth over

Above: This artist's concept illustrates the first known Earth Trojan asteroid, discovered by NEOWISE, the asteroid-hunting portion of NASA's WISE mission. The asteroid is shown in gray and its extreme orbit is shown in green. Earth's orbit around the sun is indicated by blue dots plane of Earth's orbit, although the asteroid also moves above and below the plane. The object is about 50 million miles (80 million kilometres) from Earth. The asteroid's orbit is well-defined and for at least the next 100 years, it will not come closer to Earth than 15 million miles (24 million kilometres). "It's as though Earth is playing follow the leader," said Amy Mainzer, the principal investigator of NEOWISE at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "Earth always is chasing this asteroid around." A handful of other asteroids also have orbits similar to Earth. Such 140 trillion times—that's a lot of water." Murphy and colleagues found the wet black hole using a spectrograph attached to the ten-meter Caltech Submillimetre Observatory on the summit of Mauna Kea in Hawaii. The team also revealed that the unusually warm water cloud is bathing other gases and dust around the black hole. In fact, there's enough gas and dust present that the black hole could grow to be 6 times its current size— or more than 120 billion times the mass of our sun, Murphy said. Perhaps even more surprising is that the colossal cosmic reservoir formed when the universe was a mere 1.6 billion years old. "To me, the most exciting aspect of this

objects could make excellent candidates for future robotic or human exploration. Asteroid 2010 TK7 is not a good target because it travels too far above and below the plane of Earth's orbit, which would require large amounts of fuel to reach it. "This observation illustrates why NASA's NEO Observation program funded the mission enhancement to process data collected by WISE," said Lindley Johnson, NEOWISE program executive at NASA Headquarters in Washington. "We believed there was great potential to find objects in near-Earth space that had not been seen before." www.nationalgeographic.com

discovery is that it demonstrates how pervasive water is even at a tenth the current age of the universe," Murphy said. "The fact that we have detected such a large amount [of water] at this early stage in the universe is another indication that molecules and chemical enrichment of galaxies were able to occur so rapidly after the big bang." Astronomers are hoping to use the find to study how large quantities of water in the young universe may have acted as efficient coolants of the interstellar medium—the thin gas and dust that exists between stars—possibly affecting star formation and the evolution of galaxies such as our Milky Way. www.nationalgeographic.com

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Midlands Astronomy Club Magazine

Bucket List Object #7: The Green Flash

New moon discovered orbiting Pluto

Over the next several months, we present our totally subjective list of ten celestial sights to see before you die, or “kick the bucket”, as they say. We call it the “Bucket List for Backyard Stargazers”. Our list is targeted at the casual stargazer, with no special expertise or training or ambition other than to see some of the most beautiful, and in some cases, transient sights in nature. For some of these objects, you’ll need access to a pair of binoculars or a small http://www.youtube.com/watch?v=GEoKFZ4GS_Y telescope. Others require travel and good timing and luck. And for others, you need to simply look up. But all these sights are not that hard to see, once you know how and when and where to look Another tip: the green flash lasts longer at far northern or southern for them. We’ll help you with that. latitudes where the sun takes longer

NASA's Hubble Space Telescope has spied a previously unknown moon around Pluto, bringing the dwarf planet's total number of natural satellites up to four. Astronomers estimate that the tiny fourth moon is between 13 to 34 kilometres wide. By contrast, Pluto's largest moon, Charon, is 1,043 kilometres across. The dwarf planet's other moons, Nix and Hydra, are both in the range of 32 to 113 kilometres wide. The new moon has been given the temporary designation P4. But this moniker is "just a license plate to refer to it until we get a name, and we're working on that, but we don't yet have a proposal to make," said Alan Stern, principal investigator of NASA's Pluto-bound New Horizons spacecraft and a member of the P4 discovery team. Pluto's fourth moon is located between the orbits of Nix and Hydra, which Hubble also discovered in 2005. Astronomers first spotted P4 in Hubble pictures taken June 28 using the Wide Field

Camera 3 instrument. The new moon was confirmed in Hubble pictures taken July 3 and July 18. The team had been taking the long -exposure shots of Pluto because they were looking for theorized rings around the planet. The moon probably wasn't seen in earlier Hubble images because the exposure times were shorter. It's possible, the scientists say, that P4 appeared as a very faint smudge in Hubble images from 2006 but was overlooked because it was obscured by scattered light reflecting from Pluto, said team member Mark Showalter, an astronomer at the SETI Institute in Mountain View, California. After all, the new moon is only about 10% the brightness of Nix, he noted.

"For all these years that people have been studying Nix and Hydra with the Hubble Space Telescope, they never actually did the much longer exposures that you need to do to see something much fainter nearby," Showalter said. Now that scientists know about P4, the New Horizons team can plan closeup observations of the tiny moon when the spacecraft reaches the Pluto system in 2015. Like Pluto's other moons, P4 was likely born in the aftermath of a cataclysmic collision between the dwarf planet and another planetsize body in the early solar system, around 4.5 billion years ago.

Ganymede - The only moon in the solar system with its own magnetic field Gas giant Jupiter features some epic aurora beyond-borealis (and On Jupiter the idea is the same but ultra-australis) and the causes make ours look like two small the energetic particles come from considerably cooler sources. Hubble sparklers in a bucket of water. On Earth auroras are caused by the interaction between the solar wind and the upper atmosphere. Energetic particles slam into the upper atmosphere, slowing down and losing energy to electrons in the atoms already there. More electrons gain energy from magnetic fields in the solar wind p a r tic les violently r ew ir ing themselves and our magnetosphere. Excited electrons from both processes then fall back down to their original state, emitting light as they go - different colours coming from different materials in the atmosphere.

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the sunset over an ocean is a good bet, and Key West is one of the most famous places to see the green flash. A flat prairie, or desert, or mountain range can work as just well. Even a sunset seen from an airplane. But the flash is only visible for a couple of seconds, as you can see in the video below (itʼs more impressive when you see it live):

The smashup flung molten rock into Pluto's orbit, which cooled and coalesced to form the moons. "Almost certainly [P4] is another piece created in the giant impact that created Charon" and Pluto's other small moons. And Pluto may be harbouring yet more diminutive moons that are waiting to be discovered, he added. With the New Horizons mission nearing its target, "we're going to go look and see." www.nationalgeographic.com

shine as they collide with the moon's host planet. We're going to repeat that: a volcanic moon triggers vast light shows by erupting onto a vast planet. We don't even need to send that to Hollywood, the sheer coolness of the sentence ensures he'll see it somehow.

images show huge "auroral footprints", moving radiation zones following the moons. Ganymede www.dailygalaxy.com causes one by being the only moon in the Solar system with its own magnetic field, which constantly interferes with J up i te r ' s fa r larger one. Io, on the other hand, is famous for its volcanoes volcanoes which spew highly charged particles Above: Diameter comparison of the Jovian moon which spark and Ganymede, Moon, and Earth.

Visit the quaint but noisy tourist town of Key West, Florida, and you'll have no shortage of things to see. Harry Trumanʼs “Little White House”. Jimmy Buffetʼs Shrimp Boat recording studio. And Ernest Hemingwayʼs old home, now a museum, conveniently situated near the tall lighthouse that guided the great writer home as he stumbled in a drunken haze from Sloppy Joeʼs or the Green Parrot. As night falls on Key West, a large crowd gathers in Mallory Square at the foot of Whitehead Street. Most are there to browse the tourist shops and see the buskers. But some have come to see the dramatic sunset over the Gulf of Mexico, and a few hope to see a rare and beautiful sight… the fleeting “green flash” of light that appears on the sun's limb as it vanishes over the horizon… and which comes in at #7 on our Bucket List of celestial sights to see before you die. Like a rainbow, the green flash is an effect of our atmosphere. When the sun sinks low on the horizon, its light passes through a thick layer of atmosphere which scatters blue and green light out of the line of sight, making the sun appear red-orange. As the redorange disk sinks out of sight, our atmosphere bends (or refracts) the sun's light from below the horizon. So when we see the sun's disk just above the horizon at sunset, the sun has already set. We’re just seeing an image of the sun refracted from below the horizon.

Left: A closeup of a green flash during a setting Sun.

light from this sliver sets first, followed by orange, yellow, green, blue, then violet, which sets last. This is the essence of the green flash.

you a hint of what the green flash looks like. You can only see the green flash if you have a clear view of a cloudless horizon over a great expanse of atmosphere. Looking at

to set. The flash, like sunsets, is most short-lived in the tropics. And yes, you can see the green flash at sunrise as well. But please be careful when you try to see this lovely sight. Don't stare at the setting sun or you will surely suffer eye damage. Instead, wait until the sun is almost down. Glance towards the sun briefly with your peripheral vision. And when you sense the sun has nearly set, take a careful look for this rare and beautiful sight. Not many people know of the green flash, and far fewer ever get to see it. If you have a clear view of the horizon, as over an ocean or mountain range, try to see this sublime and fleeting sight. And check one more off your celestial bucket list. www.oneminuteastronomer.com

But wait! Since blue and violet light are refracted more than green light, why don't we see a blue or violet flash instead? Sometimes we do. But unless the air is very clear, blue and violet light are scattered out of the line of sight by the air molecules of our atmosphere… the same effect that makes the sky blue. So green is the most common colour that makes it all the way to an observers eye.

As the sun's image continues to sink, we eventually see only a sliver of light above the horizon. Since The image at the top the air bends green, blue, and of the page gives violet light more than red, the red

Above: Close ups from Florian Schaaf's North Sea sunset sequence. The overall sunset was an inferior mirage type ending in a classical green flash close to the sea horizon. However, two other green flashes occurred 42 and 11s before the sun disappeared.

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Midlands Astronomy Club Magazine

Getting Started - The Plough as an Observing Aid Only a handful of constellations are easily recognisable to just about anyone who looks up at the night sky: Orion, with its belt of 3 stars lined almost perfectly in a straight line, The Pleiades as a tiny cluster above the head of Taurus, and Cassiopeia with its unmistakable 'W' shape. Apart from these, the most recognisable asterism in the night sky must be The Plough (or the Big Dipper for North American observers). Part of the larger constellation of Ursa Major, or the Great Bear, it has been recognised by man since the earliest writings found on Earth. It is circumpolar, meaning it is visible all year round, changing position through the seasons as it rotates around the Pole Star, Polaris. From the image shown you can see the 7 main stars of the Plough and their names: Alkaid, Mizar (with its double companion, Alcor), Alioth, Megrez, Phecda, Merak and Dubhe. It is good to know these when pointing out the routes to other stars and astronomical targets in the sky. The names come from Greek and Arabian lore. Stories about its existence originate with the Greeks, Chinese and Native Americans. The Plough itself is a relatively close group of stars, themselves lying not far from Earth. The closest star, Mirak, lies 78 light years away while the furthest, Dubhe is only 124 light years away. The double pairing of Alcor and Mizar are in fact a binary star system, separated by only 3 light years. For centuries the Plough has been used as a guide to finding other celestial delights and targets. The following 'How to find' targets each have objects easily found with a decent pair of 10 X 50 binoculars or larger and even small amateur telescopes. How to find: Polaris Follow a straight line from Merak through Dubhe heading upwards and the next bright star you come to is Polaris. Often called the North Star and the Pole Star it is also wrongly named as the brightest star in the sky – this would be Sirius in Canis Major. From an observer's perspective in the northern hemisphere it appears that Earth rotates on its axis pointing to Polaris. This is indeed the case but it is only coincidence that a bright star

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lies at almost the exact point of 90 degrees elevation in relation to the equator. When you look at Polaris you are facing north. All other objects rotate around this point in the sky. How to find: Arcturus Follow the curve of the Plough's handle from Megrez to Alkaid in an arc and the first bright star you come to is orange Arcturus. Arcturus is the brightest star in the constellation Bootes, the brightest in the northern hemisphere and the 4th brightest star in the sky. It shines as a bright, yellow star and has been confused by inexperienced observers as Mars. Relative to our Sun, Arcturus moves quite fast through space at 122km/sec towards the Sun. It will never collide with the Sun but will makes its closest approach in around 4,100 years time. It is only slightly larger than our Sun and lies around 36.7 light years away. How to find: Spica Continue the arced line mentioned above past Arcturus heading downwards and the next bright star you find is Spica, brightest star of Virgo and 15th brightest star overall. It is a blue giant that would consume 10 Suns and lies 260 light years away. It is actually a binary star with a companion so close it orbits Spica every 4 days. Located along the ecliptic it is sometimes eclipsed by the Moon. How to find: Gemini Follow a straight line from Megrez through Merak right across the sky

and you will come to the next bright star of Pollux. To the right is his brother Castor: they are the heads of the twins of Gemini. One myth from Greek mythology portrays that when Castor died because he was mortal, Pollux begged his father Zeus to give Castor immortality. He did so by uniting them together in the heavens. How to find: Cygnus Follow a line drawn from Phecda through Megrez all the way across the sky and next bright star you come to is Albireo, the tip of the head of Cygnus, the Swan. Also known as the Northern Cross by some, Cygnus lies along the path of the Cygnus Arm of our Milky Way. You can see this as a background haze stretching from horizon to horizon with Cygnus along its path. How to find: Regulus Follow a line drawn from Megrez through Phecda down and the next bright star you come to is Regulus, the King Star of the constellation Leo and its brightest. Regulus has the awkward accolade of perhaps contributing to the story of the Bethlehem Star in that, between 3BC and 2BC Jupiter thrice circled the star in both proper and retrograde motions – the planet (or wanderer) known as the King Planet circling the King Star? Surely a significant event.

Midlands Astronomy Club Magazine How to find: Cassiopeia Follow a line from Mizar through Polaris and you will come to the constellation of Cassiopeia. One of the mos t easily recognis ed constellations by simply looking like a large 'W' or 'M' depending on the time of year. Cassiopeia lies along the Cygnus arm of the Milky Way. Further Help Any good book store will be able to help you get star atlases of any kind to help you know your way around the sky. You can also download many free software programmes from the internet. One of the most recommended is Stellarium, which can be downloaded from www.stellarium.org. This programme, featured regularly at astronomy club meetings provides many options for display and animation of the night sky on your computer, enabling to jump forward and back in time also.

Seanie Morris is the Secretary of the Midlands Astronomy Club (MAC) having been a member since 1990 when it used to be known as the Tullamore Astronomical Society (TAS). Seanie's favourite astronomical interests include meteor watching, deep sky telescope objects and the Moon. www.midlandsastronomy.com

"Soccer Ball" Nebula discovered by amateur astronomer A dying star's wheezing cough has puffed out a gas shell reminiscent of a big blue soccer ball, scientists say. The discovery could shed new light on the shaping of planetary nebulae—so called because 18th-century astronomers using early telescopes mistook the stellar clouds for gas-giant planets. Amateur astronomer Matthias Kronberger discovered the soccerball nebula, called Kronberger 61, in January 2011 after poring over digitized photos of sky surveys from the 1980s. After he alerted professional astronomers, the Gemini Observatory in Hawaii zoomed in on the region to create the new, colour-composite image.

When a star similar to the sun fuses most of its hydrogen into helium, then the helium into carbon, the star becomes unstable and puffs out into a red giant. The hot core collapses and begins to pulsate, eventually shedding its outer layers of gas to set the stage for the birth of a planetary nebula. When the core is exposed, its radiation heats the ejected gas, Kronberger 61 lies roughly 13,000 making it glow. light-years away in the Cygnus constellation and is almost perfectly How planetary nebulae can form round—an oddity when compared such complex structures, however, with the other 3,000 or so is a hot debate among professional p l a n e t a r y n e b u l a e a l r e a d y astronomers such as Jacoby. One discovered. camp suspects a dying star requires the gravitational and/or "Very few are this spherical. magnetic "interference" of a They're usually elongated and look celestial partner—perhaps another like butterflies and other objects," nearby star or very large planet— said astronomer George Jacoby of to create a planetary nebula's the Giant Magellan Telescope complex shapes. Another camp O r g a n i z a t i o n i n P a s a d e n a , thinks that the complex shapes, California, who helped image the including butterfly-like clouds, can form without the help of nearby nebula with Gemini. companions.

"In the case of [Kronberger 61], we'll find out a year from now," when NASA's planetfinding Kepler space telescope will have finished staring at the hot star at the centre of the nebula. If the star seems to periodically dim and brighten over the year, it's likely that a big orbiting companion helped form the soccer ball -like seams. Brightening would Above: The nebula is named for Austrian Mattias imply that the Kronberger, who is a member of the amateur group lighted-up side of Deep Sky Hunters. They discovered the nebula while an orbiting object is searching near the northern constellation of Cygnus. facing the Earth, as when sunshine reflects off the when it begins to die some five billion moon. Dimming, meanwhile, could years from now. "The sun is right on mean an object is passing in front the edge of being able to do this. It's of the star, or that the companion not quite massive enough," Jacboy (and its lighted side) is passing said. "I suspect it'll have trouble." behind the star. www.nationalgeographic.com

Our own sun may or may not puff out and light up like Kronberger 61

clouds at high altitudes. Those shown green are intermediate clouds. Red and brown colours are clouds at low altitude unobscured by high clouds, and the deep blue These false-colour images from NASA's Cassini spacecraft colour is a thin haze with no clouds chronicle a day in the life of a huge storm that developed from a below. The base of the clouds, small spot that appeared 12 weeks earlier in Saturn's northern where lightning is generated, is mid-latitudes. It was the largest and most intense observed on probably in the water cloud layer of S a t u r n ' s Saturn by NASA’s Voyager or Cassini spacecraft atmosphere. The storm As seen in these Cassini images, hemisphere storms observed by clouds are likely the storm encircles the planet - Cassini. made out of whose circumference at these water ice latitudes is 186,000 miles. From The highest clouds in the image cover ed by north to south, it covers a distance are probably around 100 millibars c r y s t a l l i z e d of about 9,000 miles, which is one- pressure, or 60 miles above the ammonia. third of the way around the Earth. regular undisturbed clouds. These false colours show clouds at Taken about 11 The storm encompasses an area of different altitudes. Clouds that hours - or one 1.5 billion square miles, or eight appear blue here are the highest Saturn day times the surface area of Earth. and are semitransparent, or apart, the two This storm is about 500 times the optically thin. Those that are mosaics below area of the biggest of the southern yellow and white are optically thick consist of 84

Saturn Agonistes --1.5-Billion square -mile storm as wide as Earth

images each. The mosaic in the middle was taken earlier than the mosaic at the bottom. Both mosaics were captured on Feb. 26, 2011, and each of the two batches of images was taken over about 4.5 hours. www.dailygalaxy.com

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Midlands Astronomy Club Magazine

Perseid meteor shower

Happy anniversary, Neptune!

The Perseid Meteor Shower is caused by debris coming from the Comet Swift-Tuttle. One of the main components of comets is ice. So when a comet passes near the Sun, a part of it vaporizes and is ejected from the main body. The ejected components form a stream of particles that follow the outline of the comet's orbit. When the Earth intersects with this path (or in other cases, come close to it), the particles then enter the Earth's atmosphere.

July 11, 2011 marked the first full orbit of the planet Neptune since its discovery on the night of September 23-24, 1846. But there’s a lot more to learn about this anniversary than just the date. Step inside and let’s find out… Pinpointing Neptune is a wonderful story. For many years we’ve been taught that the discovery of Neptune was done by mathematical calculations. This came about in 1821 when Alexis Bouvard was publishing his findings for Uranus and noticed a gravitational perturbation. This led him to hypothesize an unknown body was crossing the path. Enter astronomer John Adams…

working on a proposed orbit, but it would be several years later before Urbain Le Verrier verified its exis te nce thr ough physica l observation – at the same time as Johann Gottfried Galle. Says Sheen; “It is often said that Adams never published his results. In fact a published paper was printed by November 1846 and appeared in the 1851 Nautical Almanack published in 1847.”

“It is more likely that Adams realised that his proposed orbits were moving ever closer to a “forbidden” zone of resonance.” says Brian Sheen of Roseland Observatory. “Uranus orbits in 84 years, Neptune in 165, nearly a 2:1 resonance, this brings about much greater perturbations than were being measured. In fact the mid 19th century is a quiet period and much bigger swings are evident now.”

Unknown to both at the time – and in a great twist of irony – Galileo had actually observed Neptune on December 28, 1612, and again on January 27, 1613, but didn’t realize it was a planet. Small wonder he thought it was a fixed star, because as luck would have it, Neptune turned retrograde at the same time as his first observation! But Galileo was a great observer and made drawings of his find. Given all that we know today, it’s pretty astonishing his limited equipment was able to perceive the blue planet, let alone

In 1843 John Couch Adams used the data Bouvard proposed to begin

Above: (1) Upper atmosphere, top clouds. (2) Atmosphere consisting of hydrogen, helium, and methane gas. (3) Mantle consisting of water, ammonia, and methane ices. (4) Core consisting of rock (silicates and nickel -iron).

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realize its minor movement against the ecliptic meant something. After all, the very concept of the ecliptic plane was new! “It has been known for several decades that this unknown star

Once in the atmosphere, gravity pulls them downward into a high-speed plunge. Because they are mostly very small, virtually all of them readily ignite and disintegrate. We then observe them as streaks of light as they burn up. They can number by the hundreds to hundreds of thousands per hour, hence the name meteor shower.

Above: A picture of Neptune taken by Voyager 2, showing off the Great Dark Spot which has since disappeared from the planet's surface. was actually the planet Neptune,” says University of Melbourne p h y s ic i s t, D a v id J a m i e s on . “Computer simulations show the precision of his observations revealing that Neptune would have looked just like a faint star almost exactly where Galileo observed it.”

terms, that’s just a whisker. So can you see Neptune in the night sky? Because of its small size, I recommend using a telescope for stability and printing a map from a planetarium program for more detailed star fields. It’s certainly not going to look like the Voyager image above, but you can expect to see a slightly blue coloured disk that averages about magnitude 8 (well within reach of smaller scopes). If you have never seen Neptune before, compare it in your mind’s eye to one of Jupiter’s moons and you’ll be able to pick it out of starry background much easier.

On July 11 it was the anniversary of Neptune’s first full barycentric orbit – a celebration that has taken us 164.79 years of waiting to celebrate. However, don’t expect Neptune to be in the exact same position in relation to the celestial sphere as it was when discovered. www.universetoday.com While over 150 years is but a wink in the cosmic eye, it is certainly more than enough time for our solar system to have shifted That having been over simply said, at 21:48 and 24.6 seconds UT on July 11 Neptune returned to its exact longitudinal position in respect to the invariable plane. Is it close to its discovery point? It was within 1.5 arc seconds of its 1846 location relative to the Above: Bands of high-altitude clouds cast shadows on barycentre. In visual Neptune's lower cloud deck.

The Perseid meteor shower is always seen from Earth as if coming from the constellation Perseus. It is for this reason that the Perseid meteor shower, and all other meteor showers for that matter, is named as such. The apparent source of the shower is more commonly known in astronomy circles as the radiant.

Observed since 2,000 years ago, the Perseid meteor shower is also known to some Catholics as the 'tears of Saint Lawrence' because the time when it peaks (early August) usually coincides with the saint's martyrdom. The event actually begins in mid-July but usually peaks at around August 1012. This is the time when our planet is bathed inside the densest portion of the debris stream. times, you may 10 meteors per the peak times, be visible in just

However, for as long as you have a clear sky and standing in a dark area, you can easily spot the streaks of light wherever you are on Earth. If you're lucky, you can even catch a fireball. A bright moon can also prevent you from viewing the shower in all its magnificent glory.

The meteor shower is most visible in the Northern hemisphere.

Sometimes, a brilliant streak of light caused by an Iridium flare can be mistaken for a fireball. Newbie

In the non-peak catch less than hour. But during 60+ of them can one hour.

Fun facts about the Perseids! The Perseid meteor shower is named for the constellation Perseus, from where the meteors appear to originate.

The Perseid meteor shower is one of the most prolific showers of the year, with an average peak rate of 100 streaks per hour.

Above: The Perseids should offer their best viewing in the evening hours of the 12th of the month and peak on the 13th. The shower will appear to radiate from the Northeast from the constellation of Perseus.

of about 26 mps, but, when combined with Earth’s orbital speed of about 18 mps, enter our atmosphere at a velocity rate of about 44 mps.

The meteoroids associated with the Perseid meteor shower enter the Earth’s atmosphere at about 37 mps.

http://www.universetoday.com

Comet Swift-Tuttle leaves new C o m e t debris each time it passes our planet – every 130 years. This debris field has the appearance of several streams, each measuring millions of miles long.

The Swift-Tuttle debris streams are comprised of small widelyspaced particles. Most of the meteoroids are about the size of sand grains, but some may be as large as small pebbles.

Meteors are the visible paths of Our planet encounters space With a core diameter of about vaporizing space debris as it encounters our planet’s atmosphere. This debris range in size from dust particles to small pebbles, and occasionally larger stones.

As a meteoroid enters the

debris every day, thus meteors are actually visible all year long. Occasionally, Earth passes through thicker patches of debris, known as streams or swarms, resulting in a meteor “shower.”

Earth’s atmosphere, it is heated by friction, which vaporizes the debris and causes the gases to glow. Most meteoroids disintegrate at about 50 miles above the surface, but become visible at about 40-75 miles.

Meteoroid streams, or swarms,

Meteoroids orbit the Sun just

been associated with the ancient debris field of Comet 109/Swift-Tuttle.

like planets, comets, and asteroids. They travel at speeds

have orbits similar to those of comets, thus are believed to be fields of comet debris resulting from a comet’s closing approach of the Sun.

The Perseid meteor shower has

astronomers can easily be fooled because the Perseid meteor shower can cover a big part of the sky. The Iridium flares actually come from any of the 66 satellites that make up the Iridium Satellite Constellation.

26km, comet Swift-Tuttle is the largest known object, and one of the oldest comets, to regularly pass closely to our planet.

Comet Swift-Tuttle was originally recorded by Chinese astronomers in 69 BC and 188AD, but was formally discovered in 1862, by Lewis Swift on July 16, and by Horace Parnell Tuttle on July 19. Three others also independently discovered this comet: Dudley Observatory’s Thomas Simmons; Antonio Pacinotti and Carlo Toussaint from Florence, Italy; and Danish Astronomer Hans Schjellerup.

Swift-Tuttle was “rediscovered” in 1992 by Tsuruhiko Kiuchi, ten years after its expected return of 1982. That year, the comet reached 5th magnitude, making it easily visible thr ough binoculars.

Comet Swift-Tuttle will pass within 14-million-miles of our planet when it next returns in 2126. Scientists believe that the comet will be even brighter than the 1992 pass, possibly even bright enough to be seen without binoculars.

Astronomers once believed that comet Swift-Tuttle might, in the relatively near future, pass close enough to actually impact Earth or the Moon. While continued observations and recalculations have dispelled that concern for at least the next 2,000 years, this comet remains one the greatest known solar system threats to our planet.

Perseids StarBQ You are invited to our free StarBQ on the 6th Aug. See page 12 for full details.

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