StarGate Truss Tube Dobsonian 20''- S11910


Regular price $6,999.00 Sale


The 20” fused conical parabolic primary mirror is exclusively designed for the Skywatcher Stargate. It’s thinner construction is lighter in weight than a traditional primary and allows the mirror to cool down more quickly. Both the Stargate primary and the cast cellular secondary are topped with 94% reflective coatings, for bright, sharp views at a limiting magnitude of 16. The dual-speed 2” Crayford focuser is sturdy and lets you make coarse and fine adjustments, and the included 2” to 1.25” adapter allows you to use 1.25” eyepieces and accessories as well as 2”.

Fast Optics for Reasonable Eyepiece Height

The Skywatcher 20” Stargate has a fast f/3.95 focal ratio to enhance light-gathering and keep the eyepiece height to a maximum of 79” at zenith. This means that while you will need a step-stool or ladder to view objects high overhead, most adults will be able to forego the use of a ladder when objects are closer to the horizon.

Modular Components for Easy Transport

The Skywatcher Stargate Truss-Tube Dobsonian is quite striking to look at and is designed to break down into several pieces for easy transport and storage. When unassembled, it can look a bit daunting to put together, but due to labeled truss anchor points, you can assemble your Stargate Dob in only 20 minutes! Each of the components is made of metal, including the truss tubes, azimuth and altitude bearings, base, mirror box, and secondary/focuser structure with a built-in light shield. The six truss tubes each separate into two pieces that are only 36” long, making it easier to store and transport. You will love the smooth, easy movements in both altitude and azimuth due to the steel bearings and a Teflon surface. Three 2.3 pound counterweights (included) allow you to adjust balance, and adjustable feet on the base assist you in leveling the telescope.

Comes with Finder, Two Eyepieces, Shroud, and More!

The Skywatcher 20” Truss Tube Stargate Dob comes with several accessories so that you can start observing right out of the box. Sky-Watcher has included two eyepieces (28mm and 10mm) for low and medium magnification options. A 9x50 optical finderscope is also part of the package, and a collimation eyepiece will help you keep your optics aligned. To increase your contrast and protect your mirror from light bounce and dew, a ribbed fabric shroud is included.

Sky-Watcher 20” Stargate Truss-Tube Dobsonian Highlights
  • 20” fused conical primary mirror
  • Cellular secondary mirror
  • 2" dual-speed Crayford focuser
  • Two section truss poles provide compactness for easy transport
  • Minimalist all-metal design
  • Fast f/3.95 optics for short eyepiece heights
  • 20” aperture gathers 56% more light than a telescope with 16" aperture
  • 94% reflectivity coatings
Sky-Watcher 20” Stargate Truss-Tube Dobsonian Specifications
  • Optical Design: Dobsonian
  • Primary Aperture: 508 mm (20")
  • Secondary Diameter: 134 mm minor axis
  • Secondary Obstruction by Area: 7%
  • Mirror Coatings: 94% aluminum
  • Glass Type: Borosilicate
  • Focal Length: 2000 mm
  • Focal Ratio: f/3.95
  • Light Gathering: 56% more than a 16" telescope
  • Eyepiece Height at Zenith: 79"
  • Rayleigh Limit: 0.28
  • Dawes Limit: 0.23
  • Limiting Magnitude: 16
  • Minimum Magnification: 72x
  • Maximum Magnification: 1000x
  • GoTo: No
  • Focuser: 2" dual-speed Crayford
  • Included Eyepieces: 10 mm, 28 mm LET
  • Included Finder: 9x50
  • Counterweights: (3) 2.3 lbs.
  • Other Included Items: Shroud, truss clamps
  • Upper Cage Weight: 12 lbs.
  • Truss Pole Weight: 2.6 lbs. each, 16 lbs. total
  • Mirror Box Weight: 70 lbs.
  • Dobsonian Base Weight: 40 lbs.
  • Fully Assembled Weight (with Counterweights): 138 lbs.