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 due to the difficulty in making a Hyperbolic mirror. However GSO, best known for their excellent Newtonian optics have been able to mass produce such mirrors and offer an instrument that is superior in most aspects to a conventional Schmidt-Cassegrain, yet still comes at a very affordable price.
This 8" F8 Astrograph was designed for full illumination of "35mm format" (24 x 36mm) sensors. 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.
Since the optical layout of the RC uses no lenses or corrector plates there is no false colour at all.
To further enhnace the performance of this small Astrograph, we offer various focus options, from motorisation of the standard focuser to full focuser upgrades.
The GSO RC has a generous back focus allowing you to attach many accessories like e.g. off-axis-guiders, filter wheels etc.
Each GSO telescope we supply is carefully checked and collimated before supply.
Type: True RC (Ritchey-Chretien) with a hyperbolic primary and a hyperbolic secondary mirror. No glass corrector plates or lenses in the optical train
Optical Characteristics Aperture 8" (203mm)
Focal Length 1624mm
Focal Ratio F8
Primary Mirror Quartz - Surface quality 1/12 Lambda or better with 99% dielectric high-reflectivity coating
Secondary Mirror Quartz. 99% dielectric high-reflectivity coating. Collimatable cell.
Tube Carbon Fibre tube with metal primary and secondary mirror cell, weight 6.1kg
Computer-optimized baffles Tube uses computer-optimized baffles for optimum suppression of stray light.
Focuser 1:10 Monorail focuser for extremely smooth focusing. No image shift and up to 5kgs load capacity. The focuser accepts 2" and 1.25" accessories.
Dovetail mounting rail A GP-style dovetail rail is mounted on the top of the OTA and a 3" Losmandy format on the underside of the tube.
Scope of Delivery
8" F8 RC Astrograph
2" focuser with 1.25" adaptor
1 x Vixen GP Dovetail Plate
1 x Losmandy Dovetail Plate
2 x M90 50mm Extension Tubes
Weight 6.2 kg
Obstruction 85 mm
Tube length 580 mm incl. focuser
Tube diameter 230 mm
Prism rail length 395 mm
NOTE: For use with a diagonal you will require the following extension tubes. For 2" diagonal 50 mm, for 1.25" diagonal 80 mm