Quote:
Originally Posted by bigjoe
Just goes to show Paul, it's not as easy as some might suggest.
A big scope you have really, 9 1/4 with its flatter field than most SCT's; would have been very good for this, but not the 130mm refractor that's interesting!
You did everything right as per list, so well done! 
PS: A personal first too. Sirius B is something every Amateur should bag.
bigjoe. |
I am probably not being entirely fair on the refractor which was very very nice to observe through and gave lovely low powered views of the same objects that we were observing at higher power through my SCT. Mainly M42 and Eta Carina.
In it's defence time ran out to stack on the power, with the EP we had handy for it we were limited to about 115X mag though it might still have been doable with more patience. Hopefully I get the chance to view through it visually again (It is chiefly used as an astrograph by its owner) and if it is still early enough in the season, have another crack splitting Sirius with it from home.
Something I found very interesting was the difference in the airy disc between my C925 and the big dob. The SCT at high power produced a disc looking pretty much exactly as the Celestron manual would lead you to expect when collimating, basically a small but sort of broken, fuzzy disc made up of lots of little concentric ring sections buzzing around the centroid of the image. The dob produced a noticeably tighter and cleaner star image which led to better apparent separation between the two with the obvious addition of diffraction spikes from the secondary spider vanes. The biggest issue was that Sirius was almost painfully bright, it was easy to project a clear image of the star on your hand a couple of feet away from the EP!