As anyone who's tried taking taking these types of photo will tell you, you can't just take a snap and be done with it. Photoshop is a necessity to bring the natural colours out, and some of these NATURAL colours are amazing.
That said, putting colour aside, pics taken with a good telescope are still not quite right. Objects more distant than what you're photographing will appear unnaturally large due to the depth of field. It's just like when you look through binoculars: say you're spying on a chick and there's a cat 20 metres beyond her. The cat will look unnaturally large. If you were actually standing closer, the cat would look smaller assuming you could see at all after the said girl has punched your lights out.
That said, putting colour aside, pics taken with a good telescope are still not quite right. Objects more distant than what you're photographing will appear unnaturally large due to the depth of field. It's just like when you look through binoculars: say you're spying on a chick and there's a cat 20 metres beyond her. The cat will look unnaturally large. If you were actually standing closer, the cat would look smaller assuming you could see at all after the said girl has punched your lights out.