in stock
in stock
GSO Dobsonian 300C - 300/1500mm Dobsonian Telescope

699,00 EUR
incl. 19 % Tax
excl. 35,70 € Shipping costs


GSD 300 C

GSO Dobsonian 300C (12")

Aperture 300mm / Focal Length 1500mm
enhanced 94% coating for a brighter image

Why should you sacrifice quality only because you want to save money? The GSO C-line was created to offer Dobsonian telescopes as cheap as possible without reducing the quality of the optics. In our opinion the result is an excellent telescope at an exceptional value for money.

Optical Performance:
The telescope is equipped with a high quality GSO parabolical primary mirror. We guarantee a diffraction limited performance.

As a result you get sharp and contrasty images of the moon and the planets as well as impressive views of countless deep sky nebulae and galaxies. Many details can be seen in these nebulae.

High Quality Focuser:
The GSD doesn't have a cheap rack and pinion focuser, but uses a high quality Crayford focuser. Even at high magnifications focusing is easy and smooth. The focuser is compatible with 2" and 1.25" accessories.

High Mechanical Quality:
The metal tube is very sturdy. The primary and secondary mirror cells hold the optical elements securely in place. As a result the GSO Dobsonians do not easily lose collimation.

Easy to operate:
The telescope is operated with ease by a single person. The weight and dimensions are small enough to be handled by one person as well. The tube will fit on the back seats of most cars.

Using a Dobsonian is very simple. The telescope is moved manually around a horizontal (azimuth) and vertical (altitude) axis. An azimuth and altitude Teflon friction bearing are used to offer good smoothness of operation.

Quality Control:
We do careful tests of all shipments so that we can guarantee a constantly high level of quality.

The GSD 300 offers spectacular views of the night-sky.

Observing with the GSD 300
Fine structures in galaxies and gas nebulae are visible that are otherwise only seen in photographs. Objects even begin to show colour!

In galaxy clusters you will be able to see several galaxies in your field of view, each of the galaxies consisting of billions of stars.

Globular clusters are resolved to the center in single stars. Fine filaments can be seen in supernova remnants like the veil nebula.

Under good seeing conditions the telescope will show splendid details also on the moon and planets. The cassini division in Saturn's rings is an easy target, as are fine structures in Jupiter's atmosphere and on Mars' surface. You only need to consider that with 300mm aperture the performance is often limited by turbulences in our own atmosphere - the telescope itself is not the limit to what you can see!

Easy Handling and Setup

Operation is still possible by a single person. For transportation you will need a station wagon or SUV at least, but the single parts are light enough to be carried by one person.

Setting up the telescope is very easy and done within minutes.

Image Quality

For best possible image quality you need high quality optics as well as optimized mechanics. The GSO Dobsonian has both. The thin spider vanes (see left image) improve contrast and image sharpness compared with a simpler spider with thick vanes.

Tracking Objects With The GSD 300C

The mount of a Dobsonian telescope is called "Rocker-Box", a fitting name for the uniquely simple and well-working design. The rocker allows you to point the telescope at any point in the sky and allows for comfortable, intuitive movement.

Moving the telescope is very simple, just push the telescope into the right direction – no need to use clamps or motors, it doesn't get more simple than this!

Since you need to move the Dobsonian manually it is particularly important that the movement be as smooth as possible. The GSD has an azimuth roller bearing for smooth operation. With a little experience 300-350x is no problem at all.

Advantages of the Crayford focuser in the GSD 300C:

=> Much smoother focus motion compared with simpler focusers
=> secure and scratch-free grip on the eyepieces through use of a brass compression ring (both 1.25" and 2")
=> no image shift. This means that the object will remain precisely in position while you focus. Simpler focusers tend to be shifted a little bit out of alignment, resulting in a relative movement of the object. This somewhat annoying effect does not occur in the Crayford focuser.
=> no play when you reverse the focusing direction. The focuser will reverse the direction in which it moves instantaneously when you change the direction in which you turn the focus knobs. In rack-and-pinion type focusers there is always a certain amount of play which causes a delay in reversing the direction.

Aperture / Focal LengthAperture 300mm / Focal Length 1500mm
Secondary Mirror / ObstructionMinor axis 70mm - linear obstruction 23.3% (approx. 5.4% surface)
Primary Mirror / SubstratePrecisely figured parabolic mirror - diffraction limited / BK7 - 94% coating
FocuserGood quality 2" Crayford focuser with 1.25" adaptor
Tube Dimensions & WeightMetal tube - length 145cm - diameter 35.7cm - weight 19.5kgs
Rocker Box Dimensions & WeightHeight 64cm - Diameter 63.5cm - Weight 13.5kgs
BearingsAzimuth Teflon Bearing - Altitude Friction Bearing (Teflon) with spring tension system
Finderscope8x50 finder with metal quick release bracket - fully multi-coated
ManualGerman or English
Thin 4-Vane Spider - More Contrast

The less diffraction the better the contrast. Thin secondary spider vanes improve contrast compared with cheap three vane or thick four vane spiders - important for the moon and the planets.

Blackened Interior of the Tube

The tube is carefully blackened inside for a good contrast and to avoid reflections.
Spring Tension System

The spring tension system prevents the telescope from moving on its own when exchanging eyepieces.

2" Crayford Focuser

The GSO Dobsonian uses a 2" Crayford focuser for a very precise and smooth focusing motion. Even at high magnifications you will precisely find focus. The focuser is compatible with 2" and 1.25" accessories.

Complete Dobsonian Telescope with Alt-Azimuth Mount (Rockerbox)

-- Optical Tube with 2" Crayford focuser
-- Rockerbox with azimuth roller bearing
-- Eyepiece
-- 8x50 finderscope - multi-coated
-- English or German manual
Computer-optimized main mirror cell

The 12" GSO dobsonians have a computer-optimized 9 point main mirror cell completely machined from metal.

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E-Mail: • Phone: +49 (0)89-1892870 • Fax: +49 (0)89-18928710
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