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Catadioptric Telescopes

Catadioptric Telescopes use both lenses and mirrors to produce an image.  The two most popular versions are the Schmidt-Cassegrain telescope (SCT) and Maksutov-Cassegrain scope (Mak).

A front-mounted corrector plate (the lens) and a primary and secondary mirror can put a large diameter mirror in a short and portable design.

SCT's and Maks tend to have long focal lengths and narrow fields of view.  The SCT has a thin corrector that is prone to dewing up.  In wet areas dew shields and dew prevention systems (heaters) may be required.

 

Examples of a Schmidt-Cassegrain telescope (SCT).  The shot to the right is an 11-inch diameter SCT on a GO TO equatorial mount.

The shots below are of the same scope (essentially) in an Alt-Azimuth fork mount.

Note the thin glass/plastic corrector at the front of the optical tube assembly.  These are susceptible to dewing over in wetter climates.  Dew shields and dew heaters allow observing in dewy conditions.

 

   

 

Questions or comments? Email:Jeff Martin