We are getting great shots of galaxies using a Nikon D3. These are ISO 1600 for over 5 minutes. In pretty much no-light.

You have to watch your noise control profiles, but the newer cameras are even better.

I shoot the D800 and just set the min shutter to 1/160 and control the aperture. I can shoot ISO6400 all day long and am usually just fine. And that's pretty much "old tech" these days, the newer cameras are even better.