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Dobsonian Telescopes


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Dobsonian Telescopes
sorted by Manufacturer
GSO Dobsonians
Good Quality Taiwanese Dobsonians
From 150mm to 300mm aperturer
Orion Intelliscopes
Dobsonians with integrated digital setting circles and computerized object locator
(separate page)
Orion StarBlast Mini-Dobsonian
Ultra-portable 113mm Mini-Dobsonian
(separate page)



A Few General Notes on Dobsonian Telescopes

Sooner or later all amateur astronomers face the same dilemma: They want the biggest telescope they can get their hands on (since, as they say, "Aperture can only be replaced by even more aperture"), but their finances draw the line terribly soon.

This is partially due to the inherent expenses for high-quality optics, but also due to the fact that a large telescope also requires a heavy - and expensive! - mount to carry it.

John Dobson (being in a monastery) faced a similar problem in the 1970's and therefore constructed and built several telescopes of a radically new design. To put it all in a nutshell, he cut out everything the telescope could spare and still remain a functional telescope. The result was the "Dobsonian telescope": A large Newtonian optical tube (Dobson actually ground and figured the mirrors himself!) mounted in what is little more than a box of wood. There are no fancy setting circles, worm gears or motor drives. You basically put all your money into big, good quality optics.

The result are very large aperture telescopes at a fraction of the cost of most conventional models!

The Dobsonian telescope design is by many considered to be the ultimate, no-nonsense telescope. It will show you extraordinary details in all fields of visual astronomy, especially deep-sky observations (that is: observations of faint objects like galaxies, gas nebulae and the like).

Still, you have to be aware that there is (in fact, that there must be!) also a limitation: Dobsonian telescopes are by design not suited for any kind of astronomical photography.

Fortunately there is a way to make your dobsonian telescope fit for astronomical photography. You take the optical tube and put it on an equatorial mount. The drawback: Obviously this means that you will need a big and heavy, and therefore expensive, mount to do that. Consider this whenever you want to buy a Dobsonian telescope and do not rule out astronomical imaging!

GSO Dobsonian Telescopes
GSO Dobsonians are made in Taiwan to a very high standard of optical and mechanical quality. If you are into visual astronomy there is no match to a Dobsonian when it comes to value for money.
Economy Line - Aperture 200mm / Focal Length 1200mm
2" focuser, good quality optics, top price offer
3695.-
Aperture 200mm / Focal Length 1200mm
2" Crayford focuser, 2" wide angle eyepiece, cooling fan, 8x50 finderscope, ...
 
Economy Line - Aperture 250mm / Focal Length 1250mm
Excellent value for money
2" Crayford focuser, 8x50 finderscope, 2" eyepiece
5795.-
Aperture 250mm / Focal Length 1250mm
2" Crayford focuser, 2" wide angle eyepiece, cooling fan, 8x50 finderscope, ...
 
Economy Line - Aperture 300mm / Focal Length 1500mm
Excellent value for money
2" focuser, 8x50 finderscope, 2" eyepiece
7995.-
Aperture 300mm / Focal Length 1500mm
The Flagship of our GSO Dobsonians: 2" Crayford focuser, 2" wide angle eyepiece, cooling fan, 8x50 finderscope, ...
 


Please send requests or online orders to: sales@teleskop-service.se



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GSO Dobsonian 200E - Aperture 200mm - Focal Length 1200mm
A low-budget, excellent quality entry into the world of 20cm telescopes!

 



 

GSD 200E - Aperture 200mm - Focal Length 1200mm

Within our GSO Dobsonian line this particular model serves a very clear purpose: To offer a large aperture and an excellent image quality at as low a price as possible. The value for money is fabulous.

At the same time the optical and mechanical quality is at the same high standard that our customers have learned to respect in all GSO Dobsonians!

Innovative features like the primary mirror cooling fan and azimuth roller bearing top off the excellent package of our 8" GSO Dobsonian.

Gas Nebulae and Galaxies in Detail
With this telescope you will be able to see fine details in planetary nebulae - remnants of old, dying stars. You will see the spiral arms in many galaxies. Large nebulae like the Veil nebula in Cygnus can be seen with many beautiful details.

The Moon and the Planets
Sharp images of the moon and the planets require excellent optics. The GSO Dobsonian has a precisely figured parabolical primary mirror for superb images. The small secondary mirror and the four thin secondary spider vanes bring along even sharper and more detailed images than would be possible with a large secondary mirror that is held by three thick spider vanes.

Grab-And-Go Setup
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!

Using the Dobsonian Mount
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!

Despite its simple design you will be able to track objects precisely even at high magnifications. With a little experience 250x (the recommended maximum magnification with this telescope) is no problem at all.
Cooling Fan for the Primary Mirror (optional)
All large Dobsonian telescopes need some time for cool-down. With special (and expensive!) mirror substrates you can reduce this problem, but the cool-down time will not be much shorter. Our GSD 200e can be equipped with an innovative new cooling-fan that effectively reduces the cool-down time by half! The cooling-fan is powered with normal batteries.
Azimuth Roller Bearing (optional)
No more hard-going movements in azimuth! Our GSD 200e can be equipped with a professional roller bearing and two metal plates. Movement in azimuth thus becomes much smoother - and if you want it a little less easy-going just put two felt pads between the bottom plates of the rocker-box. You can choose yourself how much resistance there should be!
Thin Four-Arm Spider
Our GSO Dobsonians do not have the old-fashioned thick three-arm spider as many other telescopes of this size have. With its four thin spider vanes the contrast is extremely high!

Primary Mirror: parabolical mirror - excellent image quality
Aperture / Focal Length: 200mm / 1200mm / f/8
Tube: metal tube
Weights: Tube - 9.3kgs
Rocker Box 11.2kgs
Length / Diameter: 113cm / 24cm
Accessories:
-
TS Super Plossl 25mm - fully multi-coated
with blackened lens edges (48x)
- 6x30 finderscope with quick exchange bracket

Smooth 2" Focuser
Each GSD 200e comes equipped with this excellent 2" focuser. The focuser is very smooth and has a locking thumbscrew. For 1.25" eyepieces an adaptor with brass compression ring and 2" filter thread is included.

Spring-Tension-System
With the proven Spring-Tension System our GSD 200e is properly balanced with nearly any accessories. At the same time the altitude adjustment remains comfortably smooth.

GSO Dobsonians are no one-way street!

Dobsonian telescopes are ideally suited for visual use - with no other telescope design will you get this amount of observing fun for your budget!

Astronomical imaging on the other hand is barely possible with any Dobsonian telescope. Only the very brightest objects (the sun with the proper filter, the moon, the brightest planets) can be photographed without a tracking motor.

Deep-sky objects (galaxies, gas nebulae) require long exposure times and consequently a solid equatorial mount.

Two Telescopes in One

Our idea was quite simple: As long as you desire just to enjoy the beauty of the various celestial objects and joyful hours behind your eyepiece you should set up the GSO Dobsonian as it is - as a Dobsonian telescope. Setup takes only a few seconds and you will be observing in no time. Also, this combination is very portable.

For astronomical imaging or the comfort of a tracking motor just attach the cradle rings and put the tube on an equatorial mount. (see image to the left)

Our recommendation: The Celestron ADM is a solid mount that will carry your 200mm "Newtonian" with good stability. For astro-imaging we offer a well working dual axis motor-drive. This combination will bring much joy to your astrophotographical ambitions.

More details on the ADM

Many other interesting mounts can be found here.

Please send requests or online orders to: sales@telescope-service.com

Prices
 
Article No. Short Description Price - SEK incl. VAT
GSD 200C GSO Dobsonian 200mm Aperture 1200mm Focal Length - incl accessories as described and Dobsonian mount 3695.-
Lufter Primary mirror cell with cooling fan for quicker cool-down
Price when bought along with the telescope
260.-
Rollenlager Azimuth roller bearing incl. 2 metal plates - price is only valid if bought along with the telescope 360.-
CR 230 Cradle rings for the Dobsonian 920.-
TS Eyepiece Case Beautiful aluminium case with a careful selection of eyepieces, filters and accessories. Only available in combination with this telescope.

You should compare yourself: With this eyepiece case you can save much more money than with other, so-called "special offers!"
1560.-

The TS Eyepiece and Accessory Case isn't just an assortment of randomly picked eyepieces, we have put a lot of thoughts into choosing a fine range of eyepieces that will work with nearly all telescopes. These great eyepieces are included in the TS eyepiece and accessory case:

- three excellent quality TS Super Plossl eyepieces
- one TS wide angle eyepiece
- our excellent TS Barlow lens (2x/1.5x)
- five carefully chosen TS colour filters and one grey moon filter (not just a cheap green filter)
- an adaptor for focal and eyepiece projection astro-imaging

All comes in a beautiful, foam-lined aluminium case
.......... Link to further information

Please send requests or online orders to: sales@teleskop-service.se


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GSO Dobsonian 200 - Aperture 203mm - Focal Length 1200mm - With Cooling Fan
High quality accessories: 2" Crayford focuser, wide angle eyepiece, roller bearing, ...



This telescope has particularly good quality accessories.

Gas Nebulae and Galaxies in Detail
With this telescope you will be able to see fine details in planetary nebulae - remnants of old, dying stars. You will see the spiral arms in many galaxies. Large nebulae like the Veil nebula in Cygnus can be seen with many beautiful details.

The Moon and the Planets
Sharp images of the moon and the planets require excellent optics. The GSO Dobsonian has a precisely figured parabolical primary mirror for superb images. The small secondary mirror and the four thin secondary spider vanes bring along even sharper and more detailed images than would be possible with a large secondary mirror that is held by three thick spider vanes.

Grab-And-Go Setup
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!

GSD 200 - Aperture 200mm - Focal Length 1200mm

This is the instrument that probably gets closest to the ideal "allround" visual telescope. It's high-quality mirror shows astonishing details on the moon and the planets while its large aperture of 203mm (8") gathers enough light to show virtually hundreds or thousands of faint galaxies and nebulae. This may well be the only telescope you will ever need!

Features of this telescope:
- high quality 2" Crayford focuser - zero image shift
- azimuth roller bearing for smoother tracking of the stars
- primary mirror cooling fan for quicker cool-down
- multi-coated 8x50mm finderscope
- eyepieces and accessories worth approximately 150 Euros

A comparable telescope got excellent results in a review in Sky and Telescope (January 2000, the model name was Orion Sky-Quest).

Please see the General Notes on Dobsonian Telescopes to find out why a Dobsonian might be just the telescope for you!

As focal length and mirror diameter suggest this is not a small telescope by a margin, but it is still small and portable enough not to pose any problems getting it wherever you want to set it up to observe. It will fit even in small cars.

Set up is extremely easy, as is actually using the telescope. Just push the telescope into whatever direction you want to look. You do not have to release clutches or turn any slow-motion knobs in order to slew it.

Secondary mirror obstruction is only 25%, four thin spider vanes (each only 1mm thin) keep the secondary mirror in place. Consequently contrast and definition are very good, more so than one might imagine. The GSD 200 will actually show more detail on the moon and the planets than many apochromatic refractors!

Using the Dobsonian Mount
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!

Despite its simple design you will be able to track objects precisely even at high magnifications. With a little experience 250x (the recommended maximum magnification with this telescope) is no problem at all.

Back-Focus
The Dobsonian was designed with sufficient back-focus for SLR cameras. At the same time you will find focus with most common eyepieces. Some eyepieces with a low field stop might need to be pulled out of the focuser by a little margin in order to reach focus. If you do not wish to do that you can buy the optional 35mm extension tube.



The active cooling fan reduces cool-down time of this telescope significantly.

Specifications
 
Aperture / Focal Length Aperture 200mm / Focal length 1200mm
Diameter Secondary 50mm - 25% linear obstruction
Primary mirror / substrate Precisely figured parabolical mirror - quality made by GSO
diffraction limited. Mirror substrate: BK-7 or Suprax
Focuser Precise and smooth 2" Crayford focuser - zero image shift. Incl. 1.25" adaptor with brass compression ring
Tube Metal tube - length 115cm - diameter 23cm - weight: 9.5kgs
Rocker Box Height 60cm - Diameter 50cm - Weight 11.2kgs
Finderscope 8x50 finderscope with metal quick release bracket - multi-coated
Accessories 2" wide angle eyepiece TS WA 42mm (Erfle design) - fully multi-coated
1.25" Super Plossl - fully multi-coated
Moon filter
Cooling fan
Roller bearing in azimuth
Excellent Crayford 2" Focuser & Red. 1.25"
the Crayford focuser has zero image shift and offers very smooth focus motion. Including 1.25" adaptor. Both 2" and 1.25" with brass compression ring...... further information

High Quality Accessories & Eyepiece Tray
TS WA 42
 - 2" Erfle wide angle ......  further information

TS Super Plossl 12mm ..................  further information
Moon Filter ..... more contrast for lunar viewing

8x50 Finderscope with Quick Release Bracket
The achromatic objective is multi-coated for a brighter image.
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
Industrial Roller Bearing for Azimuth - Not Just a Simple Friction Bearing
The roller bearing makes moving the telescope in azimuth much easier. If you want more friction simple felt pads will do the trick.
Spring Tension System
The spring tension system prevents the telescope from moving on its own when exchanging eyepieces.

GSO Dobsonians are no one-way street!

Dobsonian telescopes are ideally suited for visual use - with no other telescope design will you get this amount of observing fun for your budget!

Astronomical imaging on the other hand is barely possible with any Dobsonian telescope. Only the very brightest objects (the sun with the proper filter, the moon, the brightest planets) can be photographed without a tracking motor.

Deep-sky objects (galaxies, gas nebulae) require long exposure times and consequently a solid equatorial mount.

Two Telescopes in One

Our idea was quite simple: As long as you desire just to enjoy the beauty of the various celestial objects and joyful hours behind your eyepiece you should set up the GSO Dobsonian as it is - as a Dobsonian telescope. Setup takes only a few seconds and you will be observing in no time. Also, this combination is very portable.

For astronomical imaging or the comfort of a tracking motor just attach the cradle rings and put the tube on an equatorial mount. (see image to the left)

Our recommendation: The Celestron ADM is a solid mount that will carry your 200mm "Newtonian" with good stability. For astro-imaging we offer a well working dual axis motor-drive. This combination will bring much joy to your astrophotographical ambitions.

More details on the ADM

Many other interesting mounts can be found here.
Primary Mirror Substrates BK-7 and Suprax

The image quality itself is not affected by the mirror substrate. Likewise cooldown-time is nearly the same regardless of which of these substrates you choose. The integrated cooling fan shortens the cool-down time considerably.

The only difference between the mirrors is the image quality during cool-down (between 15 and 45 minutes, depending on the ambient temperature).

BK-7 reacts about twice as strongly as Suprax. This means that you can use higher magnifications sooner with a Suprax mirror. Suprax has roughly comparable thermic properties as Pyrex. Once cool-down is complete there is no difference in optical quality.

Please send requests or online orders to: sales@telescope-service.com




Collimation tools and other helpful accessories

Prices

Item No. Short description Price - SEK incl. VAT
GSD 200 BCR GSO Dobsonian 200/1200 - 2" Crayford focuser - BK-7 primary mirror  
GSD 200 SCR GSO Dobsonian 200/1200 - 2" Crayford focuser - Suprax primary mirror  
     
Chesire Collimation tool with crosshair - metal design 470.-
TS LA a well made laser collimator with side view. This price is only valid if you also buy a GSD 200. 670.-
TSV 235 2" extension tube - optical length 35mm 265.-
CR 230 Tube rings for this telescope - for mounting it on an equatorial mount 920.-
TS Eyepiece Case Beautiful aluminium case with a careful selection of eyepieces, filters and accessories. Only available in combination with this telescope.

You should compare yourself: With this eyepiece case you can save much more money than with other, so-called "special offers!"
1560.-

The TS Eyepiece and Accessory Case isn't just an assortment of randomly picked eyepieces, we have put a lot of thoughts into choosing a fine range of eyepieces that will work with nearly all telescopes. These great eyepieces are included in the TS eyepiece and accessory case:

- three excellent quality TS Super Plossl eyepieces
- one TS wide angle eyepiece
- our excellent TS Barlow lens (2x/1.5x)
- five carefully chosen TS colour filters and one grey moon filter (not just a cheap green filter)
- an adaptor for focal and eyepiece projection astro-imaging

All comes in a beautiful, foam-lined aluminium case
.......... Link to further information

Please send requests or online orders to: sales@teleskop-service.se


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Economy Line - GSD 250C - Aperture 250mm - Focal Length 1250mm
Economy line GSO Dobsonian with good 2" accessories



GSD 250 C - a powerful and very affordable telescope not only for observing the deep sky objects, but also for observing the planets with high contrast.
The image still shows the old rack and pinion focuser which has now been replaced by the better Crayford focuser.


Now the GSD 250 C comes with a good quality Crayford focuser for extra-smooth focus motion.
GSD 250 C

Why should you sacrifice quality only because you want to save money? The GSO Economy 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 the same high quality GSO parabolical primary mirror as the GSD 250 BCR and SCR. 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.

Simple Operation

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 roller bearing and an altitude Teflon friction bearing are used to offer good motion smoothness.



TS RK 32
A 2" eyepiece for large true fields of view - the eyepiece offers more field of view than any 1.25" eyepiece.
further information

Specifications
 
Aperture / Focal Length Aperture 250mm / Focal length 1250mm
Diameter Secondary 64mm - 25.6% linear obstruction
Primary mirror / substrate Precisely figured parabolical mirror - quality made by GSO
diffraction limited. Mirror substrate: BK-7
Focuser 2" Crayford focuser. Incl. 1.25" adaptor with brass compression ring
Tube Metal tube - length 121cm - diameter 31.5cm - weight: 15.5kgs
Rocker Box Height 64cm - Diameter 54cm - Weight 12.2kgs
Finderscope 8x50 finderscope with metal quick release bracket - multi-coated
Accessories 2" eyepiece TS RK 32mm
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
Industrial Roller Bearing for Azimuth - Not Just a Simple Friction Bearing
The roller bearing makes moving the telescope in azimuth much easier. If you want more friction simple felt pads will do the trick.
Spring Tension System
The spring tension system prevents the telescope from moving on its own when exchanging eyepieces.

Please send requests or online orders to: sales@telescope-service.com


Collimation tools and other helpful accessories

Prices

Item No. Short description Price - SEK incl. VAT
GSD 250 C GSO Dobsonian 250/1200 - 2" Crayford focuser - BK-7 primary mirror - azimuth roller bearing - 2" RK 32mm 5795.-
Lufter Primary mirror cell with cooling fan for quicker cool-down
Price when bought along with the telescope
260.-
Chesire Collimation tool with crosshair - metal design 470.-
TS LA a well made laser collimator with side view. This price is only valid if you also buy a GSD 250 670.-
TSV 235 2" extension tube - optical length 35mm 265.-
CR 303 Tube rings for this telescope - for mounting it on an equatorial mount 1020.-
TS Eyepiece Case Beautiful aluminium case with a careful selection of eyepieces, filters and accessories. Only available in combination with this telescope.

You should compare yourself: With this eyepiece case you can save much more money than with other, so-called "special offers!"
1560.-

The TS Eyepiece and Accessory Case isn't just an assortment of randomly picked eyepieces, we have put a lot of thoughts into choosing a fine range of eyepieces that will work with nearly all telescopes. These great eyepieces are included in the TS eyepiece and accessory case:

- three excellent quality TS Super Plossl eyepieces
- one TS wide angle eyepiece
- our excellent TS Barlow lens (2x/1.5x)
- five carefully chosen TS colour filters and one grey moon filter (not just a cheap green filter)
- an adaptor for focal and eyepiece projection astro-imaging

All comes in a beautiful, foam-lined aluminium case
.......... Link to further information

Please send requests or online orders to: sales@teleskop-service.se


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GSD 250 - Aperture 250mm - Focal Length 1250mm - With Integrated Cooling Fan

With an aperture of 250mm this telescope is a very popular combination of light-gathering power and portability.



The GSD 250 is a well made telescope with excellent optics and a very smooth Crayford focuser. The focuser has zero image shift.

10 inches (250mm) of aperture make this telescope a Deep-Sky big gun.

The TS WA 30mm 2" wide angle eyepiece
offers a far larger true field of view than is possible with any 1.25" eyepiece. That is particularly important for viewing gas nebulae and galaxies.

The secondary mirror obstruction is around 25%. This means that the GSD 250 is also well suited for lunar and planetary observations. Under good seeing conditions you will see plenty of craters, ridges and mountain ranges on the moon in finest detail. Planets, too, will make for innumerable joyful observing hours. You will see finest structures in Saturn's rings and many surface details on Mars. The telescope's large aperture brings along much easier to see colours, e.g. on Jupiter. The 12mm Super Plossl eyepiece which is in the standard scope of delivery offers an excellent contrast.

Despite all the telescope can easily be handled by one person - it will fit on the backseats of most small cars.

The GSD 250 is another sample of what I call "astronomical plug and play". Set-up and collimation take less than five minutes for experienced amateurs, you can launch into the observing session right away.

Please see the General Notes on Dobsonian Telescopes to find out why a Dobsonian might be just the telescope for you!
Using the Dobsonian Mount
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!

Despite its simple design you will be able to track objects precisely even at high magnifications. With a little experience 250x (the recommended maximum magnification with this telescope) is no problem at all.

Back-Focus
The Dobsonian was designed with sufficient back-focus for SLR cameras. At the same time you will find focus with most common eyepieces. Some eyepieces with a low field stop might need to be pulled out of the focuser by a little margin in order to reach focus. If you do not wish to do that you can buy the optional 35mm extension tube.



The active cooling fan reduces cool-down time of this telescope significantly.

Specifications
 
Aperture / Focal Length Aperture 250mm / Focal length 1250mm
Diameter Secondary 64mm - 25.6% linear obstruction
Primary mirror / substrate Precisely figured parabolical mirror - quality made by GSO
diffraction limited. Mirror substrate: BK-7 or Suprax
Focuser Precise and smooth 2" Crayford focuser - zero image shift. Incl. 1.25" adaptor with brass compression ring
Tube Metal tube - length 121cm - diameter 31.5cm - weight: 15.5kgs
Rocker Box Height 64cm - Diameter 54cm - Weight 12.2kgs
Finderscope 8x50 finderscope with metal quick release bracket - multi-coated
Accessories 2" wide angle eyepiece TS WA 30mm (Erfle design) - fully multi-coated
1.25" Super Plossl - fully multi-coated
Moon filter
Cooling fan
Roller bearing in azimuth
Excellent Crayford 2" Focuser & Red. 1.25"
the Crayford focuser has zero image shift and offers very smooth focus motion. Including 1.25" adaptor. Both 2" and 1.25" with brass compression ring...... further information

High Quality Accessories & Eyepiece Tray
TS WA 30
 - 2" Erfle wide angle ....  further information

TS Super Plossl 12mm ..................  further information
Moon Filter ..... more contrast for lunar viewing

8x50 Finderscope with Quick Release Bracket
The achromatic objective is multi-coated for a brighter image.
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
Industrial Roller Bearing for Azimuth - Not Just a Simple Friction Bearing
The roller bearing makes moving the telescope in azimuth much easier. If you want more friction simple felt pads will do the trick.
Spring Tension System
The spring tension system prevents the telescope from moving on its own when exchanging eyepieces.

GSO Dobsonians are no one-way street!

Dobsonian telescopes are ideally suited for visual use - with no other telescope design will you get this amount of observing fun for your budget!

Astronomical imaging on the other hand is barely possible with any Dobsonian telescope. Only the very brightest objects (the sun with the proper filter, the moon, the brightest planets) can be photographed without a tracking motor.

Deep-sky objects (galaxies, gas nebulae) require long exposure times and consequently a solid equatorial mount.

Two Telescopes in One

Our idea was quite simple: As long as you desire just to enjoy the beauty of the various celestial objects and joyful hours behind your eyepiece you should set up the GSO Dobsonian as it is - as a Dobsonian telescope. Setup takes only a few seconds and you will be observing in no time. Also, this combination is very portable.

For astronomical imaging or the comfort of a tracking motor just attach the cradle rings and put the tube on an equatorial mount. (see image to the left)

Our recommendation: The EQ-6 is a solid mount that will carry your 250mm "Newtonian" with good stability. A photographical variant of this mount is available. It offers a better tracking precision. This combination will bring much joy to your astrophotographical ambitions.

More details on the EQ-6
Primary Mirror Substrate BK-7

The image quality itself is not affected by the mirror substrate. Likewise cooldown-time is nearly the same regardless of which substrate the mirror is (as opposed to the common myth to the contrary). The integrated cooling fan shortens the cool-down time considerably.

The only difference between the mirrors is the image quality during cool-down (between 15 and 45 minutes, depending on the ambient temperature).

For this reason we have chosen BK-7 as standard mirror substrate for our GSO Dobsonians. We figure that the actual gain in performance is in no reasonable relation to the extra cost of more exotic mirror substrates.

Please send requests or online orders to: sales@telescope-service.com


Collimation tools and other helpful accessories

Prices

Item No. Short description Price - SEK incl. VAT
GSD 250 BCR GSO Dobsonian 250/1250 - 2" Crayford focuser - BK-7 primary mirror  
Chesire Collimation tool with crosshair - metal design 470.-
TS LA a well made laser collimator with side view. This price is only valid if you also buy a GSD 250. 670.-
TSV 235 2" extension tube - optical length 35mm 265.-
CR 303 Tube rings for this telescope - for mounting it on an equatorial mount 1020.-
TS Eyepiece Case Beautiful aluminium case with a careful selection of eyepieces, filters and accessories. Only available in combination with this telescope.

You should compare yourself: With this eyepiece case you can save much more money than with other, so-called "special offers!"
1560.-

The TS Eyepiece and Accessory Case isn't just an assortment of randomly picked eyepieces, we have put a lot of thoughts into choosing a fine range of eyepieces that will work with nearly all telescopes. These great eyepieces are included in the TS eyepiece and accessory case:

- three excellent quality TS Super Plossl eyepieces
- one TS wide angle eyepiece
- our excellent TS Barlow lens (2x/1.5x)
- five carefully chosen TS colour filters and one grey moon filter (not just a cheap green filter)
- an adaptor for focal and eyepiece projection astro-imaging

All comes in a beautiful, foam-lined aluminium case
.......... Link to further information

Please send requests or online orders to: sales@teleskop-service.se


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Economy Line - GSD 300E - Aperture 300mm - Focal Length 1500mm
Economy line GSO Dobsonian with good 2" accessories

Optical Performance

The telescope is equipped with the same high quality GSO parabolical primary mirror as the GSD 300 B and S. 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.

Simple Operation

The telescope is operated by a single person.

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

GSD 300 E - Economy Line

Why should you sacrifice quality only because you want to save money? The GSO Economy 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.



TS RK 32
A 2" eyepiece for large true fields of view - the eyepiece offers more field of view than any 1.25" eyepiece.
further information

Specifications
 
Aperture / Focal Length Aperture 300mm / Focal length 1500mm
Diameter Secondary 70mm - 23.3% linear obstruction
Primary mirror / substrate Precisely figured parabolical mirror - quality made by GSO
diffraction limited. Mirror substrate: BK-7
Focuser 2" metal focuser. Incl. 1.25" adaptor with brass compression ring
Tube Metal tube - length 145cm - diameter 36.5cm - weight: 19.5kgs
Rocker Box Height 64cm - Diameter 63.5cm - Weight 13.5kgs
Finderscope 8x50 finderscope with metal quick release bracket - multi-coated
Accessories 2" eyepiece TS RK 32mm

Please send requests or online orders to: sales@telescope-service.com


Collimation tools and other helpful accessories

Prices

Item No. Short description Price - SEK incl. VAT
GSD 300 C GSO Dobsonian 300/1500 - 2" metal focuser - BK-7 primary mirror - 2" RK 32mm 7995.-
Lufter Primary mirror cell with cooling fan for quicker cool-down
Price when bought along with the telescope
1020.-
Chesire Collimation tool with crosshair - metal design 470.-
TS LA a well made laser collimator with side view. This price is only valid if you also buy a GSD 300. 670.-
TSV 235 2" extension tube - optical length 35mm 265.-
Rohrschellen Plywood tube rings for this telescope - for mounting it on an equatorial mount 1730.-
TS Eyepiece Case Beautiful aluminium case with a careful selection of eyepieces, filters and accessories. Only available in combination with this telescope.

You should compare yourself: With this eyepiece case you can save much more money than with other, so-called "special offers!"
1560.-

The TS Eyepiece and Accessory Case isn't just an assortment of randomly picked eyepieces, we have put a lot of thoughts into choosing a fine range of eyepieces that will work with nearly all telescopes. These great eyepieces are included in the TS eyepiece and accessory case:

- three excellent quality TS Super Plossl eyepieces
- one TS wide angle eyepiece
- our excellent TS Barlow lens (2x/1.5x)
- five carefully chosen TS colour filters and one grey moon filter (not just a cheap green filter)
- an adaptor for focal and eyepiece projection astro-imaging

All comes in a beautiful, foam-lined aluminium case
.......... Link to further information

Please send requests or online orders to: sales@teleskop-service.se


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GSD 300 - Aperture 300mm - Focal Length 1500mm



The Flagship of our GSO Dobsonian line: The GSD 300.

Der GSD 300 bietet durch seine große Öffnung spektakuläre Ausblicke ins All.

Beobachtungen mit dem GSD 300
Feinstrukturen in Gasnebeln und Galaxien, wie man sie sonst nur von Aufnahmen her kennt, können Sie bereits live sehen. Ferne Galaxienhaufen sind ebenfalls in der Reichweite dieses leistungsstarken Newtons.

Kugelsternhaufen unserer Galaxie werden bereits bis ins Zentrum in Einzelsterne aufgelöst. Supernova Überreste, wie der Cirrus Nebel, zeigen eine Fülle feinster Filamente.

Mond und Planeten werden Ihnen, bei ruhiger Luft, viele Details, auch in Farbe, zeigen können. Strukturen in den Saturn Ringen oder die Monde des Jupiter als unterschiedlich große Scheibchen sind, wenn alle Umfeldbedingungen passen, kein Problem für die genaue Qualitäsoptik dieses Gerätes.

Die Bedienung ist noch von einer Person möglich. Für den Transport braucht man aber zumindest einen Kombi, da dieses Gerät nicht mehr auf der Rückbank eines Kleinwagens Platz findet.

Der Aufbau selbst ist sehr einfach, binnen weniger Minuten ist das Gerät einsatzbereit.

Using the Dobsonian Mount
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!

Despite its simple design you will be able to track objects precisely even at high magnifications. With a little experience 250x (the recommended maximum magnification with this telescope) is no problem at all.

Back-Focus
The Dobsonian was designed with sufficient back-focus for SLR cameras. At the same time you will find focus with most common eyepieces. Some eyepieces with a low field stop might need to be pulled out of the focuser by a little margin in order to reach focus. If you do not wish to do that you can buy the optional 35mm extension tube.



The active cooling fan reduces cool-down time of this telescope significantly.

Aperture / Focal Length Aperture 300mm / Focal length 1500mm
Diameter Secondary 70mm - 23.3% linear obstruction
Primary mirror / substrate Precisely figured parabolical mirror - quality made by GSO
diffraction limited. Mirror substrate: BK-7
Focuser Precise and smooth 2" Crayford focuser - zero image shift. Incl. 1.25" adaptor with brass compression ring
Tube Metal tube - length 145cm - diameter 36.5cm - weight: 19.5kgs
Rocker Box Height 64cm - Diameter 63.5cm - Weight 13.5kgs
Finderscope 8x50 finderscope with metal quick release bracket - multi-coated
Accessories 2" wide angle eyepiece TS WA 30mm (Erfle design) - fully multi-coated
1.25" Super Plossl - fully multi-coated
Moon filter
Cooling fan
Roller bearing in azimuth
Specifications
 
Excellent Crayford 2" Focuser & Red. 1.25"
the Crayford focuser has zero image shift and offers very smooth focus motion. Including 1.25" adaptor. Both 2" and 1.25" with brass compression ring...... further information

High Quality Accessories & Eyepiece Tray
TS WA 30
 - 2" Erfle wide angle ....  further information

TS Super Plossl 12mm ..................  further information
Moon Filter ..... more contrast for lunar viewing

8x50 Finderscope with Quick Release Bracket
The achromatic objective is multi-coated for a brighter image.
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
Industrial Roller Bearing for Azimuth - Not Just a Simple Friction Bearing
The roller bearing makes moving the telescope in azimuth much easier. If you want more friction simple felt pads will do the trick.
Spring Tension System
The spring tension system prevents the telescope from moving on its own when exchanging eyepieces.



Tube rings Made in Germany - they are made of birch plywood and offer an excellent stability and even vibration dampening properties.

GSO Dobsonians are no one-way street!

Dobsonian telescopes are ideally suited for visual use - with no other telescope design will you get this amount of observing fun for your budget!

Astronomical imaging on the other hand is barely possible with any Dobsonian telescope. Only the very brightest objects (the sun with the proper filter, the moon, the brightest planets) can be photographed without a tracking motor.

Deep-sky objects (galaxies, gas nebulae) require long exposure times and consequently a solid equatorial mount.

Two Telescopes in One

Our idea was quite simple: As long as you desire just to enjoy the beauty of the various celestial objects and joyful hours behind your eyepiece you should set up the GSO Dobsonian as it is - as a Dobsonian telescope. Setup takes only a few seconds and you will be observing in no time. Also, this combination is very portable.

For astronomical imaging or the comfort of a tracking motor just attach the cradle rings and put the tube on an equatorial mount. (see image to the left)
Primary Mirror Substrates BK-7 and Suprax

The image quality itself is not affected by the mirror substrate. Likewise cooldown-time is nearly the same regardless of which of these substrates you choose. The integrated cooling fan shortens the cool-down time considerably.

The only difference between the mirrors is the image quality during cool-down (between 15 and 45 minutes, depending on the ambient temperature).

BK-7 reacts about twice as strongly as Suprax. This means that you can use higher magnifications sooner with a Suprax mirror. Suprax has roughly comparable thermic properties as Pyrex. Once cool-down is complete there is no difference in optical quality.

Please send requests or online orders to: sales@telescope-service.com


Collimation tools and other helpful accessories

Prices

Item No. Short description Price - SEK incl. VAT
GSD 300 BCR GSO Dobsonian 300/1500 - 2" Crayford focuser - BK-7 primary mirror  
GSD 300 Deluxe GSO Dobsonian 300/1500 - 2" Crayford focuser - Deluxe Optics
- Suprax primary mirror
- reflectivity 96%
- P/V wave 1/6 lambda, Strehl 0.95 or better, with Zygo test report
 
Chesire Collimation tool with crosshair - metal design 470.-
TS LA a well made laser collimator with side view. This price is only valid if you also buy a GSD 300. 670.-
TSV 235 2" extension tube - optical length 35mm 265.-
Rohrschellen Plywood tube rings for this telescope - for mounting it on an equatorial mount 1730.-
TS Eyepiece Case Beautiful aluminium case with a careful selection of eyepieces, filters and accessories. Only available in combination with this telescope.

You should compare yourself: With this eyepiece case you can save much more money than with other, so-called "special offers!"
1560.-

The TS Eyepiece and Accessory Case isn't just an assortment of randomly picked eyepieces, we have put a lot of thoughts into choosing a fine range of eyepieces that will work with nearly all telescopes. These great eyepieces are included in the TS eyepiece and accessory case:

- three excellent quality TS Super Plossl eyepieces
- one TS wide angle eyepiece
- our excellent TS Barlow lens (2x/1.5x)
- five carefully chosen TS colour filters and one grey moon filter (not just a cheap green filter)
- an adaptor for focal and eyepiece projection astro-imaging

All comes in a beautiful, foam-lined aluminium case
.......... Link to further information

Please send requests or online orders to: sales@teleskop-service.se


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Errors and Omissions Excepted