Make an extremely compact and portable scope. Primary mirror is 76mm with a focal length of 138mm and the corrector plate mirror is 78mm diameter and -4000mm focal length. We believe that generates an f/20, 1520mm (60 inches) focal length scope with a tube length of about just 6 inches
Provides a sealed optical system.. Eliminates the spider needed in standard reflector scope
Maksutov-Cassegrain telescopes are a catadioptric design, meaning they use both lenses and mirrors. Mak-Casses are primarily reflecting telescopes, but they use a corrector lens to eliminate aberrations that would result from the mirror design alone. In a Mak-Cass the incoming light passes through the Maksutov corrector lens (sometimes called a meniscus corrector, because of its shape) at the front of telescope. It is reflected from a concave primary mirror at the back of the scope which focuses the light to the front of the telescope where it is reflected again by a smaller, convex secondary mirror. Finally, the light travels back through a hole in the primary mirror to the rear of the scope where an eyepiece is located for visual observing (or a camera for photographing). By folding the light in this manner, a Mak-Cass can be made much smaller than an equivalent Newtonian or refractor. Unused.
Charles O'Donnell has created a great 3D print telescope assembly for this lens: Go Now
