I learned a heck of a lot playing with my 450D for 18months. Guiding, balance, how to find and frame objects
, focusing, processing, really good swear words. I still think the humble DSLR is a good entry point for many people who may not be obsessive compulsive enough to continue with AP.
(twitch, twitch, head-shake, twitch....
)
Disappointing to see you're still suffering with the 550 though Jeanette. Might be time to go 2nd hand QHY8 if don't want to go the whole mono CCD/Filterwheel route? If its not cold enough at astrofest for the 550 you'll know its got problems...!