GSO 8? f/4 Imaging Newtonian Reflector Telescope Steel OTA (White)

8" f/4 Imaging Newtonian Telescope - for Astro Photography and Rich Field Observation

fast and diffraction limited reflector system (f/4)
high definition parabolic primary mirror, superior to standard Chinese-made mirrors
bright image achieved with forced 94% mirror coatings
excellent field illumination provided by a 70mm secondary mirror
robust mechanical design that prevents tilting or bending even under heavy camera loads
upgraded Monorail focuser featuring 1:10 dual speed transmission for greater stability compared to Crayford models
ideal for travel: tube length is only 58 cm, and the weight is just 6 kg with rings and finder scope
GSO’s 8" f/4 Newtonian telescope is a highly recommended option for both astrophotography and visual observing. High-quality coma correctors are also available for this fast imaging Newtonian.

Fast and Precision Optics
The accurately figured 8" f/4 primary mirror is constructed from BK7 optical glass for improved thermal stability. BK7 outperforms the soda lime float glass commonly used in many scopes at this price point. The mirror is enhanced with aluminum coatings achieving at least 92% reflectivity, and it is protected with a SiO? (quartz) layer for durability. The primary is mounted in a cell with six external push-pull collimation knobs on the rear, and a center mark on the mirror makes laser collimation straightforward.

When paired with a cropped-sensor DSLR or an astronomy camera like the ZWO ASI071MC-Pro with an APS-C sensor, this telescope provides a nearly 2° diagonal field of view—ample to capture the brightest sections of extended deep-sky objects such as the Andromeda and Triangulum galaxies, the Orion Nebula, and the Horsehead Nebula.

What's in the Box
200mm f/4 Newtonian optical tube assembly
2" Crayford-style linear bearing focuser with a 1.25" eyepiece adapter
8x50mm straight-through finder with bracket and base
Tube rings
8" Vixen-style dovetail rail
2" extension tube with a 35mm extension
Front dust cover
(No instruction manual is included for the OTA)

The High-Quality 2" Crayford Focuser
The package includes a 2" Crayford focuser with 1:10 speed reduction. Accessories are securely clamped with a brass compression ring, and the 1.25" reducer also features a brass ring. This focuser maintains stability even with heavy cameras attached. With the 1:10 speed reduction, precise focusing is achievable, resulting in point-like stars across the entire field.

Tube and Mounting Rings
The tube of this imaging Newtonian is fabricated from rolled steel for reliable thermal stability and is capped with die-cut aluminum end rings for added protection and rigidity. A dust cap is provided. The scope comes with two split-hinged, die-cast aluminum mounting rings lined with felt to safeguard the tube’s finish. These rings allow the tube to be rotated so the focuser and finder can be positioned comfortably. The bottom of each ring has threaded mounting holes for the included Vixen-style mounting plate (or an optional Losmandy-style plate), while the top of each ring features two M6x25mm threaded holes spaced 7.5" apart for mounting additional accessories such as a guide scope.

The tube boasts an attractive gloss white exterior and a matte black interior to minimize stray reflections and enhance image contrast. It measures 9.15" in diameter (9.3" at the end rings) and is 27.75" long, extending beyond the focuser to act as a shield against stray light. Additionally, the primary mirror cell includes a low-noise, long-life cooling fan powered by 8 AA batteries (batteries not included).