Jupiter has been giving a wonderful appearance in the evening sky and those of us who attended the September meeting at Oakhill had the bonus of seeing the rings of Saturn and the Galilean moons of Jupiter with the aid of telescopes. The latter planet has just passed opposition and will provide good viewing for some time to come. With the autumn equinox behind us there will be darkess earlier in the evening to aid observation.
The following chart represent the night sky at 11.00pm BST on the 8th of October and at 10.00pm BST on the 23rd October. To use the chart, face your southern horizon at the appropriate time and you will see the stars in the chart.
Starting from the Great Square of Pegasus which featured last month, it is easy to locate the star Alpheratz which is in the constellation Andromeda- Princess Andromeda, daughter of King Cepheus and Queen Cassiopeia in Greek mythology. The main features of Andromeda are two curved strings of stars, extending to the left of Alpheratz, the lower of which stands out more with the presence of two stars, Mirach and Almach, of around magnitude 2 while the upper curve of stars is fainter with stars of magnitude 3 to 4.5. Also, Cassiopeia is just above it and to the east. Fortunately some of the brighter stars form natural pairs with the fainter stars making the latter fairly easy to locate. The constellation Andromeda is home to one of the most famous objects in the night sky- the Andromeda galaxy also known as M31 and shown on the chart by a red ellipse. The Andromeda galaxy is visible to the naked eye (apparent magnitude m = 3.4) but good conditions are required and it helps if you know exactly where to look. From Alpheratz, jump to the second pair of stars along the curved strings and extend a line from Mirach through the fainter star and the Andromeda galaxy will be at a distance approximately equal to the distance between the stars. Don’t expect to see a beautiful coloured spiral galaxy like you see in images from the Hubble or the James Webb telescopes, more of a smudge or fuzzy star. Nevertheless the fact that you are looking at the most distant object that you can see with the unaided eye at a distance of two and a half million light years (that means that the light entering your eye set out from Andromeda two and a half million years ago) should give you a sense of achievement and some wonder.
The constellation Triangulum- The Triangle is pretty insignificant but at least its name matches its shape and its compact size makes it easy to spot just below Andromeda.
The final constellation Aries- The Ram, bears no resemblance to a lamb but in Greek mythology it represents the golden lamb whose fleece was sought after by Jason and the Argonauts. It is also one of the zodiacal constellations. Its brightest star, Hamal, is easily picked out, shining at magnitude m = 2.0.
Something to look out for
There will be quite a lot happening in the skies this month both at night and during the day. Saturn doesn’t have the brightness of Jupiter but on Wednesday 5th October it will have a close approach with the Moon giving you a better chance to locate it. The sight will be best seen above your southern horizon around 9.30pm.
Not to be outdone Jupiter will do the same on Saturday 8th above your south eastern horizon at around 9.30pm.
On the morning of Tuesday 25th there will be a partial (around 12%) solar eclipse between 10.00am and 12.00 noon. Remember not to attempt looking directly at the sun but use approved filter glasses or project using a pinhole camera. Keep a watch out for any news from WMA about the location of a public viewing using the new solar telescope.
On Friday 25th there will be a chance to catch the Orionid meteor shower so put on some warm clothing and get your deckchair out. The radiant point is close to the bright star Betelgeuse in Orion.
Finally Mars will become more prominent in the evening sky before it reaches opposition on the 8th December. It is in the constellation Taurus and it starts retrograde motion on Sunday 30th . The last retrograde motion was through Pisces and was difficult to follow due to the faintness of the stars. I remember tracking the retrograde motion of Mars through Leo many years ago and I’m hoping the bright stars in Taurus will enable a similar enjoyable experience this time.