Something like this
...but you need to be aware that most Newtonian telescope focusers don't have enough inward travel to reach focus with a DSLR camera (or most cameras). You may have to replace the focuser with a low-profile type meant for astrophotography.
You should just need to get a T-Ring to 1.25" eyepiece adapter.
I used this adapter set with my old Tamron when I first started out, and it worked great for catching bright planets and the moon.