The JMI Telescopes Piggyback Camera Mount allows you to attach any camera to the outside of your telescope. This can be done with altazimuth-mount scopes for shorter exposures of up to about 7 minutes, but for sharp pictures free of star drift that go beyond that time you'll need a properly aligned equatorial-mount telescope.
This version is a universal attachment for most 8-11" diameter Schmidt-Cassegrain optical tube assemblies, and attaches to the screws already present upon the rear of the optical tube.