I have tried this.
In short although I still have all the gear I almost never use it. That must say something. I have also only every seen one or two other people using it. I do not remember seeing anyone using a DSLR for this just bridge and compact cameras
I think you can get custom systems for some Nikon cameras. Other than that you have to get some rig to hold the camera to the scope and the choice of camera and scope lens is vital. Not all cameras work. It depends on the optics. Low zoom models are usually best you need to try them with your scope. I have a Kowa telescope and used a Canon Ixus 800 camera with it. I used a 20 times wide lens on the scope. My zoom lens for the scope was useless.
The main problem as has been said is stability. You need a cable release. I made one up myself as most cameras do not have a socket for one. However if anyone in the hide moves the floor will probably shake
Focusing is difficult as you have to use the screen. I ware glasses and found it a real problem due to the scree resolution. Also the DOF is about 1 mm at 100 meters or so it seems
.
I did get some passable shots BUT the detail was never good enough. Once you have been used to what a DSLR (or even a compact) can do I was always unsatisfied. I did get one of a Hen Harrier flying straight towards me full frame that was almost
in focus. Well sort of more or less (I am kidding myself.)
I have seen some photos that were good. Perhaps the system I had was not good enough or my skill was not.