@ Seeker: Yep. A DSLR what cost me another 1000€ (1600AUD or 1200USD) and I don't have that amount of spare money
. Maybe for Christmas next year.
Starkler: Not really, I actually don't know how I should do that. Orion states that the 8" F/5 is ideal for both visual use as astrophotography so I think it'll do fine.
But I have another question now, one about the resolution of the image. When you have a large focal length, your image will have a larger magnification then with a small focal length, right? But what calculation do you have to do to know the resolution you're shooting with?