We haven’t been favoured with particularly good observational weather recently so let’s hope that with darker evenings following the change from BST to GMT we also get clearer skies.
The chart below represents the night sky at 10.00pm on the 8th November and at 9.00pm on the 23rd November. Best viewing of what is discussed will be towards the end of the month and going into December.
If you face south, as usual, and look directly overhead you will easily find the ‘W’ shape of the constellation Cassiopeia which we continue to enjoy on its journey westwards in the evening sky. Look to the west and you should see the bright star Deneb, the tail of the swan in the constellation Cygnus, as it flies to the western horizon. So, as Altair slips below the horizon and out of sight, it’s time to say goodbye to the Summer Triangle, but this month we are looking to the east because as one constellation sets in the western sky another one appears in the east.
This month we will have the arrival of the constellation Orion- The Hunter. It’s my favourite constellation because of its distinctive shape and because it appears to have everything. It doesn’t take much to visualise a hunter from the stars in Orion and what stars they are! Orion’s right shoulder is represented by the star Betelgeuse, a variable red supergiant, varying in magnitude from about 0.3 to 1.2 and the 7th brightest star in the northern hemisphere. If Betegeuse were to replace our sun it would reach out all the way to the orbit of Jupiter. It also has the potential of going supernova but of course we do not know exactly when. Then, representing his left foot, is the blue supergiant Rigel the 5th brightest star in the northern hemisphere with a magnitude of 0.2. Between these stars is a line of three stars going from south east to north west and they represent Orion’s belt and at magnitudes of around 2 they are unmistakable. Less bright but still visible to the unaided eye is Orion’s sword hanging from his belt. The bottom star of the sword should be visible in good conditions and above this is a misty fuzzy patch which is the Orion nebula (aka M42) where star formation takes place. Try to observe it through binoculars or a telescope if you get the chance.
Because it is so easily recognisable, Orion is a good starting point for finding your way about the night sky during the winter months. Follow a line from Orion’s belt to the upper right, underneath the star Bellatrix representing his left shoulder, and you will find the star Aldebaran, a giant red star of magnitude 1 and the 9th brightest star in the northern hemisphere. It is in the constellation Taurus- The Bull, and is said to represent the angry eye of the bull. The ‘V’ shape of stars outlining the bull’s face is an open star cluster called the Hyades. Continue the line beyond Aldebaran and you find the better known star cluster- The Pleiades or Seven Sisters. Remember back in springtime we watched Venus pass close to the Pleiades which catches the unaided eye but much more is revealed if you use a pair of binoculars.
Bright stars are like the proverbial bus, you wait ages to see one then four come along at once. Our fourth star this month is Capella in the constellation Auriga- The Charioteer, lying directly above Taurus. Having followed the line to the Pleiades turn ninety degrees to the north and the bright star you see is Capella. It is the 4th brightest star visible in the northern hemisphere and shines at magnitude 0.1. Auriga is in the shape of a pentagon although the most southerly star is in Taurus.
As mentioned earlier the constellations and stars described above are presently in the east in the evening and will be better viewed later on but are highlighted so that you can enjoy them throughout the winter months.
Something to look out for
Mars continues to be an attraction and it will have a close approach with the Moon on the 25th November and this will visible throughout the evening.