DSLR won't focus with refractor telescope?

I have a Nikon D5200 with the appropriate T-ring and adapter for my Celestron 90EQ refractor. I was looking at the moon through the scope with one of the eye pieces and everything was perfect. Took out the eye piece and put my camera set up in and all was extremely blurry. I went through the full range of motion with the focus nobs on the scope and it never came in to focus. It seems like the further in I turned the nobs the smaller and more clear the image got but it was still way out of focus. Is there something I'm missing or not doing right? My Nikon does not have an internal focus motor so all focusing must done via the lens, in this case my scope. What else do I need?

This is a common problem with most telescopes, which are set up for visual observing. Look at any eyepiece, and you'll see that the field stop is somewhere around where the eyepiece sits in the telescope focuser. Because of the reflex mirror in a DSLR, the focal plane of the camera is about 45 mm back of where the T-mount sits. You would have to move the focuser in about 45 mm to reach the same focus as the eyepiece. Fortunately, with a refractor or Cassegrain, you can simply remove the diagonal to usually get enough in-travel. Just put the camera directly in the focuser. Reflector telescopes don't use diagonals, so don't have this freedom. So, ditch the diagonal for photography: it will only give you mirror images anyway.