Vixen (telescopes)

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Vixen is a Japanese company that makes telescopes, binoculars, spotting scopes and accessories for their products.

They have created two unusual varieties of catadioptric telescopes both with open tube design, rather than the usual meniscus.

[edit] Klevtsov-Cassegrain

This design is a modified Maksutov-Cassegrain design. It has an open tube rather than a corrector plate and provides correction of aberrations via a two element miniscus corrector lens in front of the secondary. This design was originally envisaged by G. I. Popov with a practical implementation by Yu. A. Klevtsov. The 8 inch employs a refractor style rack and pinion focuser while the larger apertures move the primary mirror as in most other Cassegrain designs. It is produce in 8, 10.25 and 13 inch aperture models.

[edit] Vixen Sixth-Order Aspheric Cassegrain (VISAC)

Vixen produces an 8 inch aperture modified Cassegrain design they refer to as a VISAC (Vixen Sixth-Order Aspheric Cassegrain) that is based on the Richey-Chretien design but adds a "field corrector lens" in the draw tube of the focusser to correct field curvature in wide field applications. The design is purported to have no coma. This particular design is also unusual in that it is a Cassegrain design but has a fixed primary and refractor style rack and pinion focuser.