GSO 20" f/8 RITCHEY-CHRETIEN CARBON TRUSS OTA
GSO
GSO 20" f/8 RITCHEY-CHRETIEN CARBON TRUSS OTA is backordered and will ship as soon as it is back in stock.
The Ritchey-Chrétien telescope is the most popular optical design used by professional astronomers and astroimagers all over the world. The Hubble Space Telescope itself uses the RC configuration.
All new GSO RC telescopes now come with a focuser upgrade kit allowing you to connect the ZWO & QHY EAF focusers without additional modification.
The Guan Sheng Optical RC's are excellent astrographs with solid build quality and precisely-figured optical surfaces. The concave hyperbolic primary and convex secondary mirrors deliver excellent correction across the field. The low thermal expansion quartz mirrors have a surface correction of 1/12th Lambda PV or better and have highly reflective dielectric coatings ensuring 99% reflectivity.
The telescope is made with a lightweight and rigid carbon fibre truss tube structure and features computer-optimized baffles to eliminate stray light.
The 20" f/8 Ritchey-Chrétien comes with a linear bearing 3" 10:1 Crayford focuser with 80mm of focus travel and clear aperture of 68mm. The focuser can be rotated 360 degrees for perfect framing. Includes a 1.25" eyepiece adapter and a selection of 2" & 1" extension rings to make connecting a variety of imaging accessories straightforward.
The rear of the telescope has a tilt plate for precise adjustment of the focal plane with M117 x 1 male threads. The 3" focuser connects to these threads on the telescope-side and has an M77 x 1 female thread on the camera-side. The focuser includes an M77 x 1 male to M74 x 1 male adapter with an internal M69 x 1 female thread.
The 14" version is pictured. The actual tube will differ slightly.
Specifications
| Optical design | Ritchey-Chrétien |
|---|---|
| Diameter | 500 mm |
| Focal length | 4000 mm |
| Focal ratio | f/8 |
| Linear obstruction | TBD |
| Corrected field | TBD |
| Backfocus distance | 400 mm from rear cell |
| Focuser thread | M77 x 1 female, M117 x 1 male (on tilt plate) |
| Weight | TBD |
| Tube outer diameter | TBD |
| Tube length | TBD |
| SKU | GSRC20A |
Items included
- GSO 20" f/8 RC Carbon Truss tube
- 3" dual-speed Crayford focuser
- M77 x 1 male to M74 x 1 male with internal M69 x 1 female thread
- M74 x 1 female to 2" barrel adapter
- 2" to 1.25" barrel adapter
- 2 x 1" M117 male to M117 female extension tubes
- 1 x 2" M117 male to M117 female extension tube
- Losmandy bars on top and bottom of tube
- Dust caps for primary and secondary mirrors
