[Dennis]

Hi Alan

For Prime Focus photography, just check that your Dob will allow sufficient “in-focus” with a DSLR attached. I understand that the focuser on Newtonian telescopes sometimes bottom out. That is, even when racked all the way in, the image in the DSLR has not yet come to focus.

Some users have solved this with using low profile focusers, low profile adapters, etc. whereas others have raised the Primary Mirror up the tube so the light cone extends further out of the focuser.

For eyepiece projection (the DSLR pointing into the eyepiece) there are special adapters that fit on the focuser and you can screw the DSLR baseplate onto the adapter to hold it steady, although a DSLR is quite heavy for this technique and may have a vignetted field of view unless you can get the camera lens very close to the eyepiece.

I suspect that attaching a DSLR plus lens to the eyepiece of a Dobsonian (eyepiece projection photography) would dramatically affect the balance of the tube. Additionally, the image of the brighter objects (such as our Moon and the Planets) would be so highly magnified that it might also be quite challenging keep the object in the field of view.

Cheers

Dennis