| The VMC200LDG’s catadioptric optical system is a sophisticated variation of the Maksutov-Cassegrain design that eliminates much of the weight and cost of conventional Maksutov optics. The Vixen optical tube starts with a Maksutov’s two high-precision spherical mirrors to help eliminate spherical aberration and yield a sharp image with no hint of false color. But it doesn’t use the thick, expensive, and heavy full aperture meniscus corrector lens found at the front of a conventional Maksutov’s optical system. Instead, the VMC200LDG uses a small meniscus corrector lens placed in the light path in front of the secondary mirror. It serves the same optical purpose as a Maksutov’s full aperture meniscus corrector lens, but in a much smaller, lighter, and less expensive form. Like a Maksutov, the Vixen offers excellent performance within the solar system, for high contrast visual observing and high-magnification eyepiece projection imaging, as well as high resolution/high power deep space observing of binary stars, globular star clusters, compact planetary nebulas, etc. As its unique design permits a much faster focal ratio than a conventional Maksutov however (f/9.8 versus a Maksutov’s f/15), the Vixen is better suited than a Maksutov for observing a wide variety of faint deep space objects – diffuse and compact nebulas, galaxies, open star clusters, etc. This gives it an advantage in all-around observing over the more expensive pure-Maksutov design. The rack-and-pinion focuser at the scope’s Cassegrain focus accepts optional 2” eyepieces and accessories. Since the focuser is external to the optical system, the mirror shift common in conventional moving-mirror catadioptric scopes is eliminated. The open tube (no full-aperture corrector lens) design eliminates the dew problem on a conventional catadioptric scope’s corrector lens that is also common with Schmidt- or Maksutov-Cassegrain systems. No cumbersome dew shield or power-hungry dew heater system is needed to keep the VMC200LDG free of image-degrading dew all night long. An optional light baffle is available to improve the image contrast in areas high in unwanted ambient light. Its standard equipment carrying handle, compact size (only 21.1” long), and light weight (only 13 lbs.) make it very easy to transport. It is an ideal size and weight to use with an optional medium payload German equatorial mount such as the Vixen Sphinx or GP-D2 Great Polaris. Particularly noteworthy is the scope’s ability to be very precisely collimated for optimum image quality. Pairs of push-pull collimation screws are available to tweak the collimation of the primary and secondary mirrors, as expected. What’s not expected, but is most welcome for collimation accuracy, is the ability also to collimate the focuser drawtube with the optical path. Here are some comments from a review the VMC200LDG received. According to Excelsis.com telescope reviews, “I have owned several SCTs and this is by far better optically than those SCTs . . . If you are looking for a portable 8” all-round telescope with a very good quality you should consider this scope.” The Vixen VMC200LDG comes standard with a 7x50mm finderscope in a quick-release dovetail bracket, a 2” eyepiece adapter, a dual T-thread flip-mirror 1.25” star diagonal with dual 1¼” eyepiece adapters, a convenient carry handle, and a dovetail mounting rail that fits Vixen Sphinx and Great Polaris mounts, as well as Celestron CG-5 Advanced Series mounts (both conventional and go-to) and the Meade LXD-75 go-to mount. An optional mounting alternative for use with other mounts (such as those from Losmandy) is the Vixen 232mm tube rings sold separately. |
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