GSO 10" F/8 Ritchey Chretien Telescope

GSO 10" F/8 Ritchey Chretien Telescope

The GSO 10" f/8 Ritchey-Chrétien Astrograph is a top choice for astrophotographers. Built with a stable carbon fiber truss tube and equipped with a precise 3" dual-speed Monorail focuser, this telescope delivers exceptional performance.

Designed as a true Ritchey-Chrétien telescope, the GSO 10" f/8 Truss Tube Astrograph offers outstanding imaging capabilities, even with large-format sensors. It's also well-suited for visual observing, delivering sharp and detailed views through its powerful optics.

Despite its capabilities, the telescope remains portable and can be mounted on EQ6-class mounts.

Features

• 10” f/8 true Ritchey-Chrétien optical system with hyperbolic mirrors
• Carbon fiber truss tube with CNC-machined aluminum and stainless steel parts
• Quartz mirrors with low thermal expansion properties
• 99% reflectivity multi-layer dielectric coatings
• Integrated rear cooling fans
• Focuser mount isolated from mirror and baffle tube
• 3" MONORAIL focuser offering increased stability
• Includes dust caps and finder shoe
• Provides a large, corrected field without requiring additional optic

Carbon Fiber Truss Tube Structure

The lightweight carbon fiber trusses offer strength and minimal thermal expansion, reducing focus shifts caused by temperature changes. This design ensures consistent optical alignment regardless of telescope orientation by maintaining equal flex across all trusses.

Focuser Technical Specs

• Travel distance: Approx. 80 mm
• Clear opening: 68 mm
• Mounted on a stable steel guide rail
• Micro-focus capability with 1:10 reduction ratio
• 360° rotation possible
• Compatible with 2" accessories or M68 thread (ideal for TS 2.5" off-axis guider

Optical Performance

Both the primary and secondary mirrors are hyperbolic and made from low-expansion quartz. They are finished with highly reflective 99% dielectric coatings for superior contrast and durability. The primary mirror is securely mounted in a fixed metal cell, while the collimatable secondary mirror includes a center mark for easy alignment.

Cooling System

To reach thermal equilibrium quickly, the rear cell includes three built-in fans. These fans help stabilize the telescope’s internal temperature, improving image quality and reducing focus fluctuations. They operate via an external battery pack that requires 8 AA batteries (not included).

Fixed Primary Mirror Advantage

Unlike Schmidt-Cassegrain, EHD, ACF, and Mak-Cassegrain telescopes which focus by shifting the primary mirror (introducing potential image shift), the RC design uses a fixed primary. This completely eliminates image shift and simplifies collimation.

How RC Design Outperforms SCTs with Correctors

Unlike SCTs such as Celestron EHD or Meade ACF, which use integrated lens correctors, the Ritchey-Chrétien is a purely reflective system. This results in a brighter image and no need for glass correctors in the optical path, preserving light transmission.

Advantages of the RC Design for Astrophotography

The GSO RC Astrograph is a genuine Ritchey-Chrétien reflector using only mirrors—no lenses are needed to correct optical aberrations. Compared to systems like Schmidt-Cassegrains or Maksutovs, which rely on spherical mirrors and correctors, or Newtonians needing coma correctors, the RC delivers superior photographic results with no chromatic aberration and excellent correction across the field.

Mount Suggestions

• To support the 15.2 kg weight (plus focuser and camera), a sturdy mount is essential. Recommended options include:
• Skywatcher EQ6 or AZ-EQ6 Goto / Orion Atlas
• Celestron CGEM or CGEM-DX
• iOptron CEM60Losmandy G11