GSO Dobson 12" Deluxe F/5 M-CRF telescope

A large telescope built following the Newtonian design, featuring a 304-mm parabolic primary mirror. Newtonian telescopes excel in observing all types of celestial objects, but due to their relatively high aperture compared to other reflectors, they are particularly effective for viewing faint objects such as nebulae, galaxies, and star clusters.

The main mirror boasts a 304 mm diameter, a focal ratio of f/5, and a focal length of 1500 mm, manufactured from premium BK7 glass. Mounted securely in a robust cell with three attachment points, the secondary mirror rests on a thin yet strong spider, which significantly reduces potential image distortions from unwanted reflections. Enhanced aluminum coatings provide a reflectivity of approximately 93%, as specified by the manufacturer.

Installation uses a dedicated Dobsonian box mount that eliminates the need for cardinal direction or polar alignment, enabling simple adjustment along both azimuth and altitude axes. Dual metal trunnions in a fork-style holder secure the telescope on both sides, each featuring a locking knob for a stable grip.

Smooth, effortless rotation along the azimuthal axis is made possible by integrated roller bearings. The construction’s low center of gravity and use of rigid materials enhance stability compared to equatorial mounts. GSO telescopes are also fitted with an optical tube balancing system tailored to the weight of the eyepiece installed.

A Crayford focuser with 10:1 micro-reduction, crafted from precision CNC-machined aluminum, delivers highly accurate focusing, even with challenging eyepieces. Two oversized adjustment screws are included; one enables full focus lock, while the other provides smooth resistance control. The supplied adapter is compatible with both 1.25” and 2” eyepieces. Movement remains flawless and precise thanks to four bearings and a roller, with no looseness in the mechanism. Maximum load capacity reaches about 3 kg.

A 12V fan positioned beneath the primary mirror boosts airflow for expedited cooling. The power source is an included holder for 8xAA batteries.

Included in the package:
- 35 mm extension tube
- 1.25" 9 mm eyepiece
- 2" 30 mm eyepiece
- Straight 8x50 finder
- Primary mirror cooling fan
- Battery holder

Technical data
Optical system: Newtonian
Aperture: 304 mm
Focal ratio: 4.9
Light-gathering power (compared to the naked eye): 1886 x
Focal length: 1500 mm
Stellar magnitude limit: 15.9 magnitude
Maximum useful magnification: 456 x
Eyepiece focal lengths / magnification: 30mm / 50x, 9mm / 167x
Eyepiece extractor diameter: 2" with a 1.25" adapter
Tube diameter: 365 mm
Central obstruction: 75 mm
Tube weight: 19.5 kg
Tube length: 1450 mm
Type of eyepiece extractor: Crayford microfocuser 1:10
Finder: optical straight 8x50
Maximum resolving power: 0.46 "
Mount type: Dobsonian
Mount control: manual
Weight (mount): 13.5 kg
Weight (total): 33 kg
Manufacturer: Guan Sheng Optical, Taiwan