Cassegrain Telescope

I am sure you are well familiar with refractor scopes and reflectors, but what about Cassegrain telescope? This telescope, which was designed in the 1600’s by French teacher and priest Laurent Cassegrain, is a sort of reflector telescope the mechanism of which involves the secondary mirror reflecting the light into a focus through a small hole located at the scope’s primary mirror.

Cassegrain is actually an adaptation of the Gregorian scope. The convex mirror of the Cassegrain possesses a cross section having a shape of a hyperboloid. On the other hand the primary type of mirror is shaped as paraboloidal.

A hole is found on the middle part of the primary mirror of the Cassegrain telescope. Here is where the light passes through and placed on Cassegrain focus.

Another type of Cassegrain telescope is the reflector type. This is known to be much more compact as compared the the Newtonian telescope with similar focal length. It should be noted that it is much easier to mount a bulky or heavy instrument or device onto the Cassegrain focus than if it is done on the Newtonian scope focus.
Image credit: OLDSKOOLDAVE