Hi Sam,
I'm not sure that camera is any good for planetary? You may wish to consider getting a DSLR for the dob, so that you can record video (for planetary photography) and deep space objects up to 20-25seconds at a higher ISO. Both are possible. Or perhaps you could buy a good planetary dedicated camera to get some better planetary shots and maybe a second hand DSLR for the deep space stuff.
Click on my flickr page if you want to see what kind of results you can expect with a DSLR, i have the 12" SW goto so it would be similar.
http://www.flickr.com/photos/80336656@N07/
All the best
Rusty