The Night Sky May 2018
Constellation of Hercules.
On an early summer night, the constellation Hercules is a very dominant sight as it is one of the biggest constellation in the night sky. Heracles, the Greek version of Hercules, was famous for undertaking twelve tasks or ‘Labours’. As the new moon is on 15th May, it is a good time to spot what Hercules has to offer. Although the stars that make up Hercules are faint, here is the time and place to find it. Looking east over to Bolton Abbey from Embsay late on the 15th you will see Vega (remember Lyra from last month) and to the right of it is the constellation of Hercules. Not impressive at first glance. The ‘ body’ of Hercules is shaped like a keystone, his limbs protruding from each corner. There are many remarkable objects to observe in and around this constellation and in particular are two globular clusters Messier 13 (M13) and Messier 92(M92).
M13 has a more inspiring title, the Great Hercules Globular Cluster. It has about 1,000,000 stars grouped together still within our galaxy. It is really only possible to be seen by the naked eye on a dark clear night. It appears as a fuzzy, faint blob but get some binoculars and take another look! (See image). Edmond Halley (of Halley comet fame) was the first person to spot it in 1714. M92 is another cluster, although smaller and further away. See the diagram for their positions. I have marked other objects for you to discover on my diagram.
Jupiter and Venus
There are a couple of opportunities to spot planets with your naked eye this month and the moon will point to their location.
Looking north-west on 17th May at about 9.30pm, you can spot the very bright planet Venus as the moon passes by. Venus is quite unusual as it rotates in the opposite direction to most other planets and it has no moons. As it has a very thick atmosphere, you will not be able to pick up any features on its surface, even with a telescope or binoculars. But if you study Venus you will see that it has phases just like the moon. To Galileo this fact finally confirmed to him that we live in a sun-centred arrangement rather than everything revolving around the Earth. He was arrested and imprisoned for drawing this conclusion!
Later on in the month around 10pm on 27th May the Moon will appear to be very close to Jupiter in the south-east and will be easy to spot. Jupiter is the largest planet in our solar system with a mass two and a half times all of the other planets put together. Alternatively, 1,300 Earths would fit inside! With a pair of binoculars, you will be able to see four of Jupiter’s moons (two either side) appear as a set of tiny specks in a very regimented line. Their current positions and names are Callisto, Ganymede, Jupiter ,Io ,Europa. These particular moons, called the Galilean moons, were the first objects to be discovered orbiting something other than Earth or the sun. Currently there are 69 know satellites of Jupiter.
Your easy challenge this month is to spot Jupiter and Venus. Harder will be to try to see the moons of Jupiter (binoculars required!) The most difficult, but rewarding challenge will be to seek out M13 in the constellation of Hercules.
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