Thank you, all, for you replies. Yes, I think it's a back focus issue but I think the back focus is not long enough. I have no adapters and the focuser is all the way in.
After I wrote this, I tried using a Barlow lens and that seemed to help. It was several hours before moonrise, and I pointed it toward the brightest thing I could find under my Bortle 5 skies. I was able to glimpse a couple of things for an instant as a I slowly scanned the area I picked out. I got a couple of quick flashes of grey on my screen but wasn't able to land on anything long enough to try any more focusing.
I appreciate the idea of getting the scope somewhat focused during the day and then dialing it in at night but that raises the question of how to keep that focus. Do you all set up your scopes during the day and then do you imaging at night?
