GSO Ritchey-Chrétien 254/2000 Carbon Tube OTA

Ritchey-Chrétien (RC) telescopes are known for their excellent optical performance, especially for photographical applications. At the same time however RCs were always notorious for being very expensive. To change this the well-known US-based distributor "Astro-Tech" asked GSO to produce true RC telescopes. GSO is best known for their excellent Newtonian optics which they have built for many years now.

The result of this joint venture is an instrument that is superior in most aspects to a conventional Schmidt-Cassegrain, and still comes at a very affordable price. Teleskop-Service is European distributor for these instruments from GSO.

The 8" f/8Astrograph was designed for full illumination of the "35mm format" (24 x 36mm). For cameras with a small sensor, particularly most CCD cameras, no field flattener is needed. For cameras with a larger sensor we recommend the use of a field flattening lens. (Currently under development.)

Since the optical layout of the RC uses no lenses or corrector plates there is no false colour at all. Also you will not need to use an IR cut filter, thus increasing the effective light-gathering power of the instrument.

The 10" f/8 RC Astrograph can illuminate a field diameter of max. ca. 60mm (including optional RC corrector). Without corrector, the usable field has ca. 30mm diameter. Here, you have a pure mirror system that can be used without UV/IR cut filter. Most of the CCD cameras are sensitive in this spectral range.

The image is absolutely free from chromatic abberations and the resulution is higher than most apochromatic refractors in this price range.