GSO f/8 Ritchey-Chretien – Carbon Fiber OTA


This GSO Ritchey-Chretien has 8” of aperture and a focal ratio of f/8. The primary & secondary mirrors are made from quartz, famous for its low thermal expansion. The optical set is multi-coated with 99% dielectric coatings. This high reflectivity coating offers higher contrast images and protection against scratching.

The optical tube assembly of the GSO 8” RC Telescope is made of low expansion, lightweight carbon fiber. The finish looks great, but beauty is only skin deep. This OTA will cool down nicely due to the properties of the carbon fiber, and it has great strength for its weight. Inside the 8 inch Ritchey-Chretien OTA 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 due to the inclusion of a D-Series Losmandy style dovetail. 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 8” f/8 Ritchey. A 1.25” adapter and a duo of spacers are also included, allowing you to make adjustments to the focus distance. One thing that really sets this 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 8” RC carbon fiber telescope tube 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.


Model Number 8RC / 10RC
Telescope Series GSO Ritchey-Chretiens
Telescope Optical Design Ritchey-Chretien
Telescope Aperture 8″ / 10″
Telescope Focal Ratio f/8
Telescope Focal Length (mm) 1624 / 2000
Optical Coatings 99% Reflectivity
Telescope Eyepiece(s) Included? No, Sold Separately
Finder Included? No, Sold Separately
Focuser Style Crayford/Crayford Style
Focuser Size 2″
Focuser Speed Dual Speed
Telescope Mount Type No Mount – OTA Only
Telescope OTA Length (in.) 21.8 /
Telescope OTA Weight (lb.) 16.4 /



GSO 8” f/8 Ritchey-Chretien Carbon Fiber 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 Ritchey-Chretien at a more reasonable price. Now serious astro-imagers can choose from closed tube or open tube RC telescopes in a wide range of apertures!



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