We are well into the wonders of the spring night sky when May begins and we òÀØmayòÀÙ take advantage of the many clear nights we have been subjected to recently and try our luck at finding some of those more difficult patterns and objects that are hidden away among the stars and moonlit sky but might indeed be that much more rewarding when they are revealed!
Also the month of May is an exciting stage for the Moon as it glides its way across the sky and offering a particularly spectacular treat for a select few countries towards the end of the month.
Great Snake with a hidden treasure:M68 is gem of a cluster in Hydra (Image credit:Kerry Scullion / Armagh Planetarium)
Last month was the perfect setting for the Lyrids meteor shower with a serene, dark, new moon night sky and this month the Eta Aquarids meteor shower steps up to the plate. Unfortunately the Eta Aquarids will more than likely be washed out by the brightest and closest full moon of the year so all but the brightest meteors will be hidden but for all those die hard meteor fans, the optimal time to watch for the meteors will be on the early hours of the morning, around 4 am on the 5 and 6 May, and watch low to the North horizon radiating from one of the oldest recognised constellations, Aquarius.
Both the southern and Northern Hemispheres will be able to witness this overshadowed meteor shower only the Southern Hemisphere may get to grace their beds that bit earlier.
Take that!Hercules shows the Hydra who’s boss!(Image credit:Getty Museum)
The first constellation we will begin with for the month of May follows the pattern of difficult to spot yet it offers some very fascinating and wonderful gifts.It is the colossal Hydra the Water Snake! Hydra is not the most well-known of the 88 constellations but it is none the less impressive! Stealing 1303 square degrees of night sky it is the largest of all the constellations but despite its size, it is not very bright so may be that bit difficult to spot. But do not give up, a great way to find this monstrous beast early in the month is to find Mars who has been sailing through the sky under Leo from April, look for a bright object with a slightly orange glow. Once youòÀÙve found the Rusty Red Planet, travel slightly to the right towards the horizon and you should arrive at a bright object that seems quite alone. This is Alphard, the brightest star in the water snake. This is actually the only bright star in the constellation and nicely enough, Alphard is an Arabic term meaning òÀØSolitary oneòÀÙ for there is not many stars in this patch of the sky. ˆàIt has an impressive absolute magnitude of -1.69 but due to it being situated 177 light years away it only appears to have a duller apparent magnitude of 1.99. Within the water snake Alphard marks the orange heart of the beast and is sometimes referred to as Cor Hydrae or HydraòÀÙs Heart. Alphard rises above the horizon before the body of the snake so it acts as a Herald, announcing the snakeòÀÙs ascension to the sky. ˆàGreek mythology states that the Hydra lived in a swamp near the small Greek town of Lerna and it devastated the countryside, killing peopleòÀÙs cattle and destroying their land. It was believed to be extremely poisonous, so much so that even the smell of its tracks would kill a man. The Hydra was eventually slain by the mighty Hercules in an epic battle.
If you enjoy searching the sky for the more difficult objects to find, you can travel down Hydras body and rest towards the tail, just below the constellation of Corvus and just above the water snakes body is the faint globular cluster M68. You will need binoculars or a telescope to view these beautiful universal òÀØartworksòÀÙ but they are worth the hard work. ˆàTo the name eye on a dark clear night it look like an extremely smudgy faint star with an apparent magnitude of 7.8, very dull indeed but that is only due to the fact it is a whopping 40,000 light years away from us. When you see a globular cluster you are witnessing a very beautiful object in the night sky. They are spherical collections of thousands of stars, in this case roughly 2000, who orbit a former galactic core and are tightly bound together by gravity, truly a marvel to witness.
Where to find the Beehive.To misquote Austin Powers, “Oh Beehive!” (Image credit:Kerry Scullion/ Armagh Planetarium)
To continue our expedition in the sky towards the more elusive treats it has to offer, look above and to the west of Hydras head there is the faintest of all 13 constellations in the Zodiac that is the constellation of Cancer the Crab.ˆà What story could there possible be to have a crab immortalised in the sky I hear to ask? It was actually quite a brave little crab. Myth has it said that this was the little crab that attacked the feet of Hercules during his mighty battle with the Hydra, in service of Zeus wife, Hera, Hercules sworn enemy. Unfortunately Hercules stamped on the poor crab and Hera placed it into the sky for all his efforts. This faint little crab in the sky amplifies itòÀÙs myth by surprising all star gazers with its offerings. Firstly whilst looking at this little crab in the sky you can look with wonder that two of its few stars have been found to have exoplanets, planets found outside our solar system, but unfortunately our basic telescopes would not be enough to view these celestial wonders, like the colossal constellation of Virgo, we can only look up in awe.ˆà But it has some treats to curb the stargazeròÀÙs appetite. It has the wonderful specimen of an open cluster called the M44 or the Beehive Cluster.ˆà It is found in the centre of Cancer, half way between the brightest star in Leo, Regulus and one of the heads of the twins in Gemini, Pollux. Big Binoculars or a telescope will be needed to see this beautiful celestial object. This hazy patch is much more visible that the globular cluster of M68 but contains much less stars, roughly 350 in fact. It is located a huge 577 light years away. Open Clusters are obviously much different to a globular cluster; these are actually stars that have been formed in the same molecular cloud, so in essence they are all roughly the same age. Unlike a globular cluster they are only loosely bound by mutual gravitational attraction and an open cluster eventually disperses after a few hundred million years. This Beehive Cluster is 400 million years old, four times the age of the more famous Pleiades star cluster and it is definitely worth the effort to gaze upon.
The constant name dropping of this next constellation in the aforementioned patterns should encourage your eyes to wonder in his direction, and at this time of the year this is a great time to see him.If you look high in the sky to the east, just to the left of Boªçtes, you will find the famous, mighty Hercules! The myths behind Hercules are quite long and you can find he has a part in many of the surrounding patterns in the sky. He was believed to be to be the son of Zeus and Alcmene, the wisest and most beautiful woman in the world. He was driven mad by the vengeful Hera, Zeus wife, and murdered his wife and children. Realising what he did he tried to make up for his crimes under the command of King Eurysteus, who set Hercules 12, seemingly impossible tasks known as the Labours of Hercules, one of these being the slaying of Hydra the water snake.ˆà The constellation is the fifth largest in the night sky but it does not possess many bright stars but it does not make it any less interesting. There are 4 stars in the centre of Hercules that make his torso and this shape is known as the asterism of the Keystone. These four stars look slightly like an out of shape square but located on the right hand side of this asterism is one of the most famous globular clusters, the M13. It can be found between the two brightest stars in the Northern hemisphere, Vega in Lyra and Arcturus in Boªçtes. Located on the right side of the Keystone facing the direction of Arcturus is this amazingly beautiful Globular Cluster.ˆà To the naked eye it looks like a hazy comet and it can be easily spotted by binoculars or a telescope. It was discovered in 1714 by Edmund Halley and with roughly half a million suns inside it, it is 12-13 billion years old, almost as old as the Universe itself. It is definitely a celestial object you do not want to ignore.
For all those Moon chasers out there this is a fantastic month for lunar gazing.Early in the month we have the Full Moon, 5May, also known as the òÀÜFlower MoonòÀÝ, which will be the closest full moon of the year, with it reaching perigee (shortest distance between the earth and the moon) at 221,000 miles from the earth. So expect a very large and bright moon on the 5th. The moon will also visit a few planets during the end of the month including a silvery crescent moon gliding close to Venus after sunset on 22 May and on 28 May it will slide below the bright orange Mars.It will finish off the month below Spica, VirgoòÀÙs brightest star, with Saturn hovering above them.
But a lucky few will get to see a much more special occurrence this month with regards to the Moon.
Solar annular eclipse of 15 Januaryˆà 2010 from Jinan, Republic of China.Image credit:ˆà A013231 via Wikimedia.org)
For those select few who will be in either China, Japan or the United States on 20-21May,ˆà you will be able to witness an Annular Solar eclipse! Now an annular eclipse, you may have guessed is not a total eclipse, it is only a partial eclipse. To explain this we need to understand the path the Moon orbits the Earth. The Moon’s orbit is not perfectly elliptical so when it is at its closest to the earth or at perigee it is 221 000 miles from us, therefore appearing bigger in appearance and able to cover the Sun, but when it is at its most distant from the Earth, at apogee, 252 000 miles, it appears smaller and it is not able to fully cover the Sun. So when it is closer and it aligns with the Sun and Earth we have a total eclipse and when it is further we have an annular eclipse. An annular eclipse is quite dangerous to look directly at as there is still harmful bright rays coming from the eclipse and normal precautions regarding telescopes and day time viewing should be adhered to but, if you are lucky enough to be residing in these countries on these dates you are very lucky indeed to see such a beautiful natural occurrence.
The next total eclipse will be in 2015 and will be visible in Asia, parts of Europe, North Africa and Iceland, including the famous Svalbard, known for having some of the most distinctive and beautiful Aurorae.
(Article by Kerry Scullion, Education Support Officer)
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