DSLRs are fantastic for astrophtography. Dedicated astrocameras are fantastic for astrophotography. So which is best… well they have different strengths. If you live somewhere that is light polluted then it is possible to shoot nebula (not galaxies – I’m afraid – just nebula) with light pollution filters but annoyingly the light pollution filters don’t work very well with regular DSLRs because regular dslrs block the very deep red wavelengths with their in built ir cut filter and letting  these wavelengths through is critical for making these light pollution filters work. So some folks get their dslr’s annoying ir cut filter removed but that then makes their camera shoot overly red pictures in the day time. There is a solution to this (an OWB filter) but it gets messy.

An astrocamera doesn’t have an annoying ir cut filter (or at least it has one which is much less aggressive) and many of them can be cooled, which really helps when you shoot with these light pollution filters (or when you shoot somewhere really dark) and best of all astrocameras are really easy to hook upto computers and then you can use one of my recommended free astro programs to control it and your mount. The only problem with astrocameras is that the sensors tend to be quite small unkess you’re willing to spend more than a grand. I have a list of my favourite astrocameras here.The problem with astrocameras is that they tend to have smaller sensors that DSLRs (unless you buy an expensive one)  and that means you catch less photons. 

My advice is when your starting out use your dslr, if you get hooked then think about switching to an astrocamera or modifying your dslr.