Vixen Catadioptric Optical Tubes

More Information  · Supplied Accessories  · Recommended Accessories  · Images of Some Features Price $1,699.00 $1,899.00 SAVE: $200.00 (10%) List Price $2,660.00 Highest Useful Magnification 360x Focal Length 1800mm Focal Ratio f/9 Resolution 0.58 arc seconds Visual Limiting Magnitude 14 Aperture 8" Weight 13.2 lbs. Warranty 5 years

The VISAC system provides pinpoint star images less than 15 microns in diameter, even at the edge of its 42mm image circle. As a 35mm film negative is only 44mm across its diagonal, you can see that the VC200L makes an excellent choice for a truly sharp photographic instrument. The pin-point stellar images also make off-axis guiding markedly easier than with an SCT. Guide stars at the edge of the VISAC field are sharper, brighter, and easier to locate than the fainter and out-of-focus field edge stars you’ll find in the curved field of an SCT.

The VISAC optical system consists of an aspheric concave primary mirror, a convex secondary mirror, and a three-element field corrector at the base of the focuser. The primary mirror does not have a simple and easy to make spherical optical figure, as you’ll find in Schmidt-Cassegrains and Maksutov-Cassegrains. Instead, it has a precise sixth-order aspheric curvature that is produced by Vixen’s unique High-Precision Poly-Order Aspherical Mirror Molding Technique. The VISAC aspheric mirror drastically reduces the spherical aberration common to Schmidt and Maksutov designs. Combined with the triplet field flattener in the focuser, the Vixen sixth-order aspheric mirror simply outperforms other catadioptric designs by a visible margin.

The VC200L optical system is well suited for visual observation and astrophotography of the Moon, planets, star clusters, nebulas, galaxies, and comets. An f/6.4 reducer lens for wide-field photographic use is also available.

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 corrector lens) design eliminates the dew problem on a conventional catadioptric scope’ 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 VC200L 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 compact size (only 24.4" long), light weight (only 13.2 lbs.), and standard equipment carrying handle makes 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.

Here’s a sampling of some reviews that the VC200L has received. According to ScopeReviews.com, “[C]atadioptric fans should take a close look at this scope, since it does offer a few advantages compared to your standard issue Schmidt-Cassegrain . . . The build quality is much better than most mass-produced SCTs. The Vixen has a 2" rack and pinion focuser, which eliminates the primary image shift in an SCT. Also, the scope is collimatable to an impressive degree . . . Finally, there’s no corrector plate to collect dew . . . The scope was collimated and remained in collimation during the test period even after being driven around in the back of a pickup truck. Stars are indeed pinpoints all the way out to the edge of the field." And another review, in the book Star Ware, 3rd edition, on page 146, “Owners comment that the VC200L yields flat, distortion-free images from edge to edge thanks to the corrector lens, while spherical aberration is minimized thanks to the aspheric primary mirror. The result is pinpoint stars from edge to edge, an important consideration for through-the-telescope photography." When all is said and done, the plain truth is that the VC200L is an outstanding visual/photographic optical system.

The Vixen VC200L 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.