if you want to learn how to take astrophotos you have a few options, frankly in my opinion don't go down the SCT path if you are beginning as the learning curve is huge and unless your a obsessive tinkerer will annoy the hell out of you.!
Start with a low weight wide field setup maybe a EQ5pro/6pro, a 80mm ED refractor and a small guide scope (i made my guide scope from a DSE 114mm newt). Mount it either Side by Side, or piggy back with piggy back being the easiest to balance. Having a DSLR is a good start and cheap, though getting something like a QHY8 OSC (one shot colour) i think would be great as they are cooled and darks frames arnt so much of a issue with them.
I don't want to scare you but if your looking to get into astrophotography it isn't cheap, it is addictive and hence will make it more expensive
. IMHO set aside at least 3k if starting from scratch and be prepared for all the little cables,leads, odd bits your going to need.!
have a look at most of the pictures in the DSO image part of this forum, and also have a look what a eq6pro/10"dob/modded 40d can do on my web page. I have been at it for a year now and im just starting to see some good results so persist and be patient as you learn more things you will get better.!