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 scopes (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. |
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