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Explore Scientific  |  SKU: ES-DOB1245-01

Explore Scientific 12" f/5 Truss Tube Dobsonian Telescope


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Explore Scientific 12" f/5 Truss Tube Dobsonian Telescope



  • 12" / 305mm Aperture
  • 1525mm Focal Length
  • f/5 Focal Ratio
  • 10:1 2" Two-Speed Helical Focuser
  • Red-Dot LED Finderscope
  • Floor-based Manual Alt-Az Mount
  • Altitude Tension Clutch
  • Dual Radial Main-Mirror Fans
  • Tool-Free Breakdown and Assembly


The Explore Scientific 12" f/5 Truss Tube Dobsonian Telescope is ideal for deep sky observations and detailed planetary views. It provides high performance at a reasonable price.

Its f/5 focal ratio and 10:1 dual-speed helical focuser make this a perfect choice for imaging as well. The fast focal ratio helps devices capture images in less time than slower scopes, while the unique focusing mechanism employed in the helical design gives it the ability to achieve sharp focusing without backlash that rack-and-pinion focusers are generally unable to achieve.

This is a Generation II telescope. All updates have been performed on this telescope. No telescope type has changed the hobby quite as much as the Dobsonian. Before the introduction of the Dobsonian by John Dobson, the vast majority of amateur telescopes consisted of small telescopes with primitive mechanics - barely enough to see the polar caps of Mars or the rings of Saturn. Larger telescopes, such as the Schmidt-Cassegrain were reserved for the wealthy. The ingenious combination of simple yet effective mechanisms with the greatest possible opening gives the Dobsonian telescope a unique triumphant march around the world. Nowhere do you get as much light for your money like a good Dobson. Disassembly of the scope without tools ensures a trouble-free transport of this great scope even in small cars. The entire structure has been optimized for maximum stiffness with minimal weight. The combination of high altitude bearings with optimized aluminum structures allows fine adjustment flows at high magnifications.

A 305mm mirror collects more than 1,800 times as much light as the naked eye. Details on planets and deep sky objects will be visible even for inexperienced observers. Bright star clusters are resolved to the core, and the sight of the terminator on the moon is an unforgettable experience.

The rocker box provides a steady observational platform with very low vibration. It features high-altitude bearings with aluminum structures that allow for fine adjustment flows at high magnification. The dual radial primary mirror fans quickly adjust the temperature to reduce mirror distortion.

The scope is ready for use with our optional coma corrector.


Browse the Explore Scientific Truss Tube Dobsonian series: 10" | 16" | 20"

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Explore Scientific 12" f/5 Truss Tube Dobsonian Telescope | ES-DOB1245-01 | 811803034433

Explore Scientific 12" f/5 Truss Tube Dobsonian Telescope



600x (theoretical)


305 mm | 12"

Focal Length

1525 mm

Focal Ratio


Field of View



0.38 arc sec theoretical limiting stellar magnitude

0.45 arc sec theoretical Rayleigh limit

15.11 mag theoretical limiting magnitude

Barrel Size



34.6" (88cm) truss pole length

.79" (20mm) truss pole diameter

15" (38cm) secondary cage assembly diameter

6.7" (17cm) secondary cage assembly height

16.7" (42.5cm) mirror box/rocker box height42.5 cm

56" (142.24cm) height to center of eyepiece at zenith


Cage Assembly: 6.5 lb , Mirror Box: 50 lb
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