The Celestron T-Adapter for Nexstar 4SE Telescopes is a sturdy aluminum T-Adapter for when you’d like to attach an SLR or DSLR camera to the smaller rear cell threads of a Celestron NexStar 4SE telescope or C90 spotting scope for prime focus photography. To get started you will need the appropriate T-Ring for your camera body (93402 for Nikon & 93419 for Canon EOS). First you remove the lens from your camera and attach the T-ring in its place. As the T-ring is camera-brand specific, it will snap right on just like a lens. Next, remove the diagonal and visual back from the rear cell of your telescope and screw the Celestron T-Adapter onto the rear cell threads until secure. Now, thread the T-ring & camera onto the T-Adapter. The camera is now using your telescope as a telephoto lens. Prime focus photography is popular for short exposure images of terrestrial objects as well as celestial objects like the Moon.