i used to use a sony nex 5n, and a 8mm rokinon f2.8 for star shots.
http://500px.com/photo/65801451 sample shot from my nex5n.
If you are on a budget, i would look into a used nex 5 or 5n, ( 5n has a better on off switch and that's about it. same sensor)
look into the new rokinon 10mm, the 8mm is a fisheye and the 10 should give a better FOV without the heavy distortion.
Rokinon , or samyang makes the best night photography lenses. and they are cheap.
The nex line lacks lenses, but for under 1000 you could have a top of the line night photography setup. which is less then most cameras.
If your not on a budget, I think the best compact camera at the moment, is the fuji xt-1, but its 1300 plus lenses.
And the A7-r ( the a7 is not worth buying) is the best camera for size and weight. if you have no budget, you would be looking at 2000 for the camera, and i think a wait on the rokinon lenses, not sure if they are out yet. and i think there 35mm is around a grand.
One more, if the weight of your old camera was ok, the canon 6d is the best star shot camera avaiable at the moment, and can be found for 1300-1400 , plus a rokinon 14mm f2.8 is the very best setup you can get.
If star shots matter, that will be your best kit.
Feel free to pm me, i just went through the process and decided on a Nikon d610, but image quality for night/star shots was my only concern, and i can feel the weight :P