How to Use a Digital SLR on a Telescope

Turn off the camera. Press then lens-release button, hold it down and turn the lens clockwise until it detaches from the camera. Insert the T-ring into the lens mount and screw it counter-clockwise until it clicks in place. Make sure you purchase a T-ring compatible with your camera, because different brands use different lens-mounting systems. Screw the T-adapter into the T-ring.

Set up your telescope in a dark location away from porch lights, street lights and other sources of light pollution.

Insert the T-adapter into the eyepiece slot on the telescope's focuser. Tighten the set screw on the focuser to secure the camera.

Turn on the camera. Set the shutter speed to "Manual" mode, and then select a shutter speed below 20 seconds in length. Longer shutter speeds require an equatorial mount with motorized tracking. Use short shutter speeds --- five seconds or less --- when imaging bright objects such as the moon and planets. Reserve longer shutter speeds for faint objects, including star clusters, galaxies and nebulae.

Turn off the camera's flash and autofocus. Set its light sensitivity level between ISO400 and ISO1600. Use ISO800 or less when photographing the moon and planets. Higher ISO settings work best when capturing faint objects beyond our solar system.

Aim the telescope at the astronomical object you want to photograph. Look through the camera's viewfinder and adjust the telescope's orientation to center the object in the viewfinder.

Adjust the telescope's focus knob until the object appears sharp in the viewfinder. Press the shutter-release button to take the picture.