Since I bought my go-to Skywatcher-102 in April (which is brilliant by the way) I have been having issues with actually getting a really good alignment during the set up process. This was purely down to the issue of having to guess where the centre of the eyepiece was.
I was out with the Well’s & Mendip Astronomers last Friday and my friend Hugh was using an illuminated cross-hair eyepiece to get his Mead perfectly centred. Why had I not thought about this?! So, out I went to the local telescope shop (MC2 in Frome) and acquired myself one. Boy did this make things much easier! Giving 2 red cross-hairs within which you can get a perfectly centred object, and therefore a great alignment. So after I had completed the alignment protocol I decided to have a look at some double stars.
As I am not familiar with double stars, I decided to use the feature in the go-to handset, and started working my way down the list.
ALMACH was my first port of call. Situated at 056°00′ +29°05′ it was in fairly good position, rising just above the end of my garden. Located in the constellation of Andromeda Almach is actually a quadruple star system located some 350 light years from Earth. However, only a double star can be resolved through a small telescope. I was viewing at 86x magnification.
The second object of the night was ALBIREO located at 188°07′ +66°37′ in the constellation of Cygnus and located approximately 430 light years from Earth. This was one that was recommended to me as a great double star, and it did not fail to impress. The pair are another great example of colour, where one is a very bright blue and the other yellow. A very nice contrast between the pair.
Targets number three and four were DABIH & ηCASS. Target number five was Mizar in the constellation Ursa Major. Located at 314°34′ +36°38′ At a distance of 82 light years, they are relatively close, in astronomical terms. They are by far my favorite double stars so far. They have a very clear bright blue colour even in the fairly light polluted surroundings of my house. Both Mizar and Alcor its companion are spectral type A.
(Image from http://astropixels.com/stars/Mizar-01.html)
The last two objects on my double star viewing adventure for that night was Polaris (yes, a double star, though the companion was very faint, it was still visible) and Rasalgthi in the constellation of Hercules. This view was very interesting, as both stars were clearly red. Its always nice to be able to see colour, and from that we can determine so many physical parameters of the star.
By this time, the mist was starting to roll in, and the temperature was rapidly dropping. So I decided to push the scope, and try and view the ice giants Neptune and Uranus. I had written in the last two editions of the OAS Magazine (http://en.calameo.com/read/001319831ab434b818f09) about where to find Neptune and Uranus, so decided to use the go-to and see what I could see.
Once the scope had finished slewing, I peered into the eyepiece. There it was, Neptune. A tiny blue disc set against a backdrop of stars. It was exceptionally small, but clearly disc shaped. I was now viewing at 130x magnification. Next stop, Uranus. Waited for the beep, and took a look. There it was. A yellowing tiny disc. The rings were not visible, but it could clearly be differentiated from the stars behind. This was the first time I had ever seen any of the ice giants through my own kit. A very impressive way to finish a successful but brief viewing session.