The Celestron Universal 1.25" T-Adapter lets you attach a telescope with a 1.25” focuser or eyepiece adapter installed to a Canon or Nikon SLR or DSLR. This allows you to capture short exposure images of terrestrial objects, and celestial objects like the Moon.This T-Adapter screws into a T-Ring (sold separately) which is designed to attach to the mounting flange of your camera. The barrel end of the T-Adapter slides into the focuser, like an eyepiece, and locks into place with the focuser or eyepiece adapter thumbscrew.