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GSO 6" f/9 Ritchey-Chretien Optical Tube - Steel OTA - 6RC

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The Ritchey-Chretien was designed for photographic use, and while you can put an eyepiece in the diagonal and use it visually, you will get less than "stellar" results. It is for this reason that we do not recommend an RC telescope for visual use. If you have any questions or need help choosing a telescope that performs well when used either visually or photographically, please don't hesitate to contact us. Thanks!

GSO 6” f/9 Ritchey-Chretien OTA

As amateur astronomers advance in their astro-imaging skills, they dream of owning a Ritchey-Chretien telescope. RC telescopes are being used in some of the world’s biggest and best observatories due to their color-free, coma-free, spherical aberration-free optics. The problem is, Ritchey-Chretien telescopes are out of the reach of most people due to their high price tag…until now!

Guan Sheng Optical of Taiwan has been creating affordable imaging telescopes for several years. After the huge success of their imaging Newtonians, they turned their attention to creating a high-quality 6-inch Ritchey-Chretien at a more reasonable price. Now serious astro-imagers can choose from closed tube or open tube GSO RC telescopes in a wide range of apertures!

This GSO RC telescope has 6” of aperture and a focal ratio of f/9. The 6-inch Ritchey-Chretien's primary & secondary mirrors are made of BK7 glass which is coated with aluminum that has a 96% reflective surface. The aluminum is then overcoated with quartz. This high reflectivity coating offers higher contrast images and protection against scratching.

Inside the 6” GSO RC telescope is a Knife-Edge Baffle System whose only job is to keep stray light out of the telescope’s interior. Stray light eats contrast for breakfast (or a late night snack) and is, therefore, our enemy. The addition of a dew shield (sold separately) will help further defeat stray light, we recommend picking one up. The OTA mounts easily to a variety of mounts that accept Vixen-style dovetails. Simply remove the dovetail if you choose to mount the telescope via cradle rings.

A high quality 2” dual speed Crayford focuser comes standard with the GSO 6” f/9 Ritchey, and you'll also get a 2" to 1.25" adapter as well as a 2" long thread-on extension and two (2) 1" long thread-on extensions. One thing that really sets this 6-inch Ritchey-Chretien telescope apart from Schmidt-Cassegrains, even though it looks like one, is the lack of image shift. In SCT’s, the focuser moves the mirror forward and back on a rail, and it is this movement that can cause image shift. The mirror of the GSO 6” RC is fixed into place, similar to that of a Newtonian…it is not connected to the focuser in any way. Removing this connection removes image shift…voila! To collimate the RC, adjustments are made to the secondary mirror.

GSO 6” f/9 RC Telescope OTA Specifications

  • Optical Design: Ritchey-Chretien
  • Aperture: 6”
  • Focal Length: 1370 mm
  • Focal Ratio: f/9
  • Mirror Material: BK7 Glass
  • Coatings: 96% aluminum with quartz overcoat
  • Optical Tube Material: Metal
  • OTA Length: 19.1”
  • OTA Weight: 12.3 lb.