Hi Sam & All,
I know I'm chiming in quite late here but I think you've made a good choice with the 10x50s Sam
. Mind you, the 9x63s would have been just as valid a choice. My 10x50s are now 34 years old and still my most used binoculars.
Just to note a couple of other things that might be helpful. There is a very cheap binocular mount that can be made out of scrap timber here:
http://www.skyandtelescope.com/howto...inoculars.html
that really works well in helping to hold them steady. An even cheaper alternative is to rest them on top of an up-turned broom (if you are tall you will need a long-handled broom) but 10x50s are
relatively easy to hand-hold steadily. If you don't believe me try the 70, 80 and 90mm binoculars first!
Fixed-focus binoculars are pretty poor -- they will be slightly mushy at all distances and particularly so on stars because stars are point sources and are therefore the most demanding on optics. Steer clear of them for astronomy.
Zoom binoculars are also a poor choice. They have generally narrower fields and will often be mushy on focus as well. Fixed magnification are best by some distance. Steer clear of zoom binos for astronomy.
Now moving on to roof-prism -v- porro-prism. In my opinion, porro-prism binoculars are inherently better than roof-prism design for astronomy. Roof-prisms typically loose 10-15% of the incoming light over porro-prisms and the image delivered to the eyepiece will accordingly be dimmer aperture -v- aperture. Roof-prisms throw away light but the advantage they have is in their slim, slightly more compact design. Roof-prism binos are also more tricky to collimate should they get bumped out of collimation (pretty rare) --porros are no more or less likely to be knocked out, but are simpler to fix.
There are a few books devoted solely to binocular astronomy and many astronomical magazines also devote a few column-inches to what you can see -- it might be worth a look there from time-to-time ...
Best,
Les D