Dobson GSD 250c
Dobsonian Telescopes from GSO are often purchased by beginners due to
their simplicity and ease of use. Dobsonian telescopes are designed for
visual observing. GSO Dobsonians have a better coating and high quality
mirrors for maximum success and fun under the starry sky. Its
cost/performance ratio is truly unbeatable.
For best possible image
quality you need high quality optics as well as optimized mechanics. The
GSO Dobsonian has both. The thin spider vanes improve contrast and
image sharpness compared with a simpler spider with thick vanes. The 94%
enhanced coating on main mirror and secondary mirror produces a
brighter image. Save up to 10% light against other telescopes with same
The simple and intuitive way to use this telescope makes it much easier
for beginners to spend their first joyful hours under the starry sky.
Set-up is as easy as you can imagine: Just put the rocker box on the
ground, insert the telescope tube and put the springs in position and
you´re ready to go!
Primary Mirror Cooling Fan
Until a mirror is properly cooled
down it will create currents of warm air that will deteriorate the image
- no matter which mirror substrate is used. Only after the mirror has
cooled down this effect stops. The Cooling Fan reduces the cooling down
Upgrade your Dobsonian
A dobsonian telescope from GSO is a
perfect starter telescope. You will get a high end optic for an
incredible low price. Later you can upgrade the telescope with
eyepieces, filters or with cradle rings to mount it upon a equatorial
mount. Than you also can start with astrophotography through your
2" Crayford Focuser
A central part of the telescope is the good 2" Crayford focuser with many advantages:
Much smoother focus motion compared with simpler focusers.
Centering and Tracking Objects
- 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
- 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.
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 is as smooth as possible. The Dobsonian has an azimuth
roller bearing for smooth operation.
For the elevation, the telescope is equipped with the Spring Tension
System. This prevents the telescope from moving for example when
- GSO Dobsonian Telescope
- Rockerbox - azimutal mount
- Fan with battery holder
- 8x50 finder with achromatic objective
- 25 mm 1.25" Super Plössl eyepiece
- 2" extension tube, length 35 mm
A good priced Dobson with very good diffraction limited optic and enhanced 94% coating