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Sky-Watcher 18" Stargate GoTo Truss Tube Dobsonian - S11920

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SKU: SKY-S11920
$6,999.00 $6,499.00
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Sky-Watcher 18” GoTo Stargate
Truss Tube Dobsonian Telescope

With the amazingly modular and completely computerized Skywatcher 18” GoTo Stargate Dobsonian you can delve into deep space from your own backyard or a dark-sky site and experience intricate celestial details that are normally only seen in photographs! With the computerized SynScan hand controller, you can quickly find over 42,000 objects and enjoy the dust lanes and detailed arm structures of galaxies and the glowing star nurseries of hundreds of nebulae. The Sky-Watcher 18” Stargate GoTo Truss Tube Dobsonian gathers a whopping 27% more light than a big 16” Dob, and on a still, dark night, you’ll be amazed at how much more you’ll see!

Fast Optics for Reasonable Eyepiece Height

The Skywatcher 18” Stargate has a fast f/4.1 focal ratio to enhance light-gathering and keep the eyepiece height to a maximum of 74.5” 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.

The GoTo version of the 18” Stargate Truss Tube Dobsonian uses Skywatcher's tried-and-true SynScan computerized system. The electronics and motors are built into the base, and the SkyScan hand controller is your easy to use interface. You can choose from multiple tracking rates (sidereal, solar or lunar) and the object database has 42,000+ celestial objects that include those from the Messier, NGC, IC, SAO, Caldwell, Double Star, Variable Star and Named Star catalog as well as, of course, the planets. The Freedom Find™ dual-encoder technology from Sky-Watcher ensures precise tracking when manually moving the telescope in both axes without sacrificing alignment. This gives users a high level of convenience and flexibility not offered in telescopes without dual encoders. For more information on pointing accuracy, encoder resolution, and the motors see the specifications below.

The 18” 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 15.9. 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”.

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 short order! 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 18” GoTo 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. Finally, a 12V DC power cord comes with this SynScan telescope package, but you will need to provide your own power supply. See specifications and/or instruction manual for more information.

Sky-Watcher 18" Stargate GoTo Truss-Tube Dobsonian Highlights


  • Fused conical primary mirror
  • Cellular secondary mirror
  • 2" dual-speed Crayford focuser
  • Two section truss poles provide compactness for easy transport
  • Spare, all metal design
  • Fast f/4.1 optics for short eyepiece heights
  • 18" aperture gathers 27% more light than a telescope with 16" aperture
  • 94% reflectivity coatings
  • Freedom Find dual encoders
  • SynScan with database of over 42,000 objects


Sky-Watcher 18" Stargate GoTo Truss-Tube Dobsonian Specifications


  • Optical Design: Dobsonian
  • Primary Aperture: 458 mm (18")
  • Secondary Diameter: 120 mm minor axis
  • Secondary Obstruction by Area: 7%
  • Mirror Coatings: 94% aluminum
  • Glass Type: Borosilicate
  • Focal Length: 1900 mm
  • Focal Ratio: f/4.1
  • Light Gathering: 27% above a 16" telescope
  • Eyepiece Height at Zenith: 74.5"
  • Rayleigh Limit: 0.31
  • Dawes Limit: 0.25
  • Limiting Magnitude: 15.9
  • Minimum Magnification: 65x
  • Maximum Magnification: 902x
  • GoTo: Yes
  • Object Database: 42,900+
  • Dual Encoders: Yes
  • Power Requirement: DC11/5A - 15V/3A
  • Motor: 0.9-degree Hybrid Stepper Motor
  • Transmission: Worm and Timing Belt plus 64 Micro-step Stepper Motor Drive
  • Gear Ratio: Azimuth 400, Altitude 1523.796
  • Resolution: Azimuth 10240000 CPR, Altitude 39009185.2 CPR
  • Tracking Rate: Sidereal, Solar, Lunar
  • Tracking Mode: Alt-Azimuth
  • Hand Control: SynScan
  • Pointing Accuracy: Up to 5 arc-minutes RMS
  • Resolution of Aux RA/Dec Axis Encoders: Azimuth 19136 CPR, Altitude 212622.2 CPR
  • 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: 11 lbs.
  • Truss Pole Weight: 2.6 lbs. each, 16 lbs. total
  • Mirror Box Weight: 62 lbs.
  • Dobsonian Base Weight: 66 lbs.
  • Fully Assembled Weight (with Counterweights): 155 lbs.