Although Celestron has their primary reputation from the production of Schmidt- Cassegrain telescopes, they have produced both Maksutov and Schmidt -Newtonian telescopes as well.
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| Orange C90 Astro | Later Model C90 w/case | |
| Celestron introduced the C90 in 1978. This was a 90mm f/11 instrument with a large helical focus ring around the perimeter of the telescope tube. Several versions of this telescope have been sold, and it can be important to know the differences. The orange tube C90's were supplied with a 5x24 finder and .965" visual back for diagonals and eyepieces. A C90 Astro version was also brought out in 1978 with a single arm fork mount and spur gear drive base. Later, the telescope color was changed to black and was supplied with a square, hard plastic case. These "mid-life" units often lacked coatings and are not as suitable for astronomy, being designed primarily for spotting purposes. These were supplied with .965" visual back as well. By the early '90s most units came with multicoatings and a rectangular foam filled carrying case and are of excellent quality. An option was also offered at this time for either .965" or a 1 1/4" visual back. The latter option was referred to as the C90 Super. Finally, a rubber covered version was produced to reduce potential damage from field use, and was given the C90R designation. | ||
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In 1983 with Halley's comet fever growing, Celestron introduced their first Schmidt-Newtonian telescope, the Comet Catcher. The 5.5" diameter f/3.64 optics delivered well corrected, wide-field views. A unique 1 ¼" focus assembly was introduced that moved the eyepiece tube and diagonal up and down along the optical centerline of the telescope rather than the conventional way of moving the eyepiece in and out. This had the advantage of being able to support a heavy camera load without image shift. | |
| Comet Catcher | ||
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The C500 was introduced primarily as a Maksutov-style photographic lens. However, it can be used very nicely as a spotting scope and as a wide field astronomy telescope as well. It's 90mm diameter f/5.6 optics are not quite as bright as a C90's due to the larger center mirror spot, but it provides such nice views of extended deep sky objects that you don't really need a finder. The optics are multi-coated, and the back allows use of a 1 ¼" diagonal as well as a T-ring for a camera mount. It is supplied with a simple photographic tripod mounting block and soft case. This same optical tube was also imported by Orion and Adorama. | |
| C500 | ||