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GSO 8" Ritchey-Chretien Astrograph Telescope


Select your finder scope preference:
No Finder
8x50 Straight
8x50 Right Angle

Affordable, portable RC Astrograph telescope with outstanding optical quality. Ideal for astrophotography.

Ritchey-Chretiens deliver images with very little distortion. They have a flat field of view, so objects are in sharp focus right to the edge of the image. The image is coma-free, so stars at the edge of the field of view remain perfectly round. And there is no false colour because they use only mirrors with no correcting lens. 

The 8" f/8 design provides enough aperture and a long enough focal length to give good image scale. It is ideal for smaller deep sky objects such as planetary nebulae, galaxies and small globular clusters. 

The primary mirror is made from optical quality quartz and is limited only by diffraction, which means they achieve the theoretical maximum resolution possible for the size of the mirror. They are machined and polished to better than 1/12 wavelength, sometimes 1/16 wavelength, which is considerably better than the industry norm. Each mirror is individually tested and hand-corrected if necessary after production, with final testing by laser interferometry.  

The open tube, quartz mirror and in-built cooling fans enable the telescope to cool quickly, with virtually no problems with dew. A computer-optimised baffle system minimises any stray light in the tube.  

Optical tube assembly only. Comes with a 2" Linear Bearing Crayford focuser, two dovetail bars, two 25mm extension tubes and one 50mm extension tube.  An optional collimation ring is available

Recommended For
What's In the Box?
  • 8" (203 mm) f/8 Ritchey-Chretien optical tube assembly
  • 2" Crayford bearing 10:1 micro edge focuser
  • 2 Vixen (V style) dovetail bars (top and bottom)
  • Two 25mm and one 50mm RC extension tubes
Optical designRitchey-Chretien
Primary mirror8" (203 mm) quartz with surface quality better than 1/12 wave RMS
Focal length1624 mm  
Focal ratiof/8 
Resolution0.57 arc seconds
Focuser Crayford 2" Linear Bearing 10:1 micro edge 
Back focus254mm From rear cell, 159mm with focuser installed
Tube length580 mm 
Tube materialAluminium
Weight of tube7.5 kg