GSO Telescope DO-GSO Dobson 8" F/6 M-CRF (GS680)

The Newton Delta Optical GSO DOBSON 8" F/6 M-CRF telescope is an excellent choice for beginners and intermediate astronomy enthusiasts who want high optical performance at a reasonable price. Its design allows for detailed observation of all Messier catalog nebulae, comets, and planets, revealing fine surface details. The telescope’s robust construction, quality optics, and reliable mechanics make it suitable for both casual stargazing and more demanding observations.

Tube Construction
The telescope uses the classic Newtonian reflector design, built from a rolled, high-stiffness metal sheet. The interior is well-blackened to minimize stray light and enhance contrast, especially when viewing bright objects like the Moon and planets.

Optical System
The primary mirror is parabolic, made from high-quality BK7 glass, with a diameter of 200 mm and a focal length of 1200 mm. It is securely mounted in a three-point cell, while the secondary mirror is held by a thin, durable spider to reduce image distortion from reflections. The f/6 focal ratio provides a good balance, minimizing coma at the edges and offering sharp images for both deep-sky and planetary observations. Enhanced aluminum coatings give the mirrors a reflectance of about 93%.

Mounting and Assembly
The telescope is mounted on a Dobsonian box mount, which is stable, easy to use, and does not require polar alignment. The fork-style holder with metal pins and locking knobs ensures secure attachment and smooth adjustment. Roller bearings enable light, smooth movement in azimuth, and the low center of gravity increases stability. The mount also features a balancing system to accommodate different eyepiece weights.

Focusing Mechanism
A standout feature is the high-quality Crayford focuser, made from precision-machined aluminum. It operates smoothly and precisely with four bearings and a roller, and includes a 10:1 microfocusing knob for fine adjustments. The focuser accepts both 1.25" and 2" eyepieces and can handle accessories up to 3 kg in weight.

Cooling System
A built-in 12V fan beneath the main mirror improves air circulation and speeds up cooling, powered by an included 8xAA battery pack.

Terrestrial Observations
This telescope is not designed for terrestrial use as the image appears inverted. However, with an erecting lens, it can be adapted for ground-based viewing, such as aircraft spotting.

Astronomical Observations

• Solar System:

  • Surface features on the Moon larger than 1.5 km

  • All planets, including Mercury and Venus phases, Mars surface details, Jupiter’s belts and moons, Saturn’s rings and moons, Uranus and Neptune as blue-tinted stars, asteroid movement, and faint comets

• Stars:

  • Up to 2.7 million stars down to 14th magnitude

  • Double and multiple stars with separations as small as 0.8"

• Nebulae:

  • All Messier objects and some from the NGC catalog

With its 200 mm mirror, the telescope provides much clearer and more detailed images than smaller models. However, image quality can be affected by light pollution, atmospheric conditions, and the accuracy of optical collimation.

Technical Specifications

• Mirror diameter: 200 mm

• Focal length: 1200 mm

• Focal ratio: f/6

• Optical system: Newtonian reflector

• Mirror shape: Rotational paraboloid

• Limiting stellar magnitude: 14

• Maximum useful magnification: 300x

• Theoretical resolving power: 0.8"

• Focuser: 2" Crayford with 1.25" adapter, 10:1 microfocusing

• Finder: 8x50 straight optical

• Included eyepieces: 30 mm 2" (Erfle), 9 mm 1.25" (Plössl)

• Optical tube weight: 11.2 kg

• Mount weight: 9.5 kg

• Total weight: 21 kg

Warranty
24 months