Skip to content

Sky-Watcher 20" Stargate GoTo Truss Tube Dobsonian - S11930

shipping truck Free shipping
SKU: SKY-S11930
$7,999.00 $7,499.00
Price match Guarantee

Sky-Watcher 20” Stargate GoTo
Computerized Truss Tube Dobsonian Telescope

Want to see deep-space like never before? The Sky-Watcher Stargate 20 Truss Tube Dobsonian will blow you away with its light-gathering power! With the computerized SynScan hand controller, you can quickly find over 42,000 objects and enjoy the extra detail, and sometimes even see a hint of color in deep-sky objects. Nebulae that are difficult or impossible to view with smaller scopes because of their low surface brightness appear in the eyepiece as if by magic, and you'll stare in wonder at the Veil Nebula, the North American Nebula, and the ever-elusive Horsehead. Objects that you thought you knew well, like the Orion Nebula or M-13, take on a whole new dimension through a big telescope like the Sky-Watcher 20” Stargate; it’s like seeing them with new eyes!

The Stargate 20”, with a full half meter of aperture, collects a whopping 56% more light than a 16” model, and let’s face it, a 16” telescope provides amazing views of the Universe! However, even though the SkyWatcher 20” StarGate Truss Tube Dobsonian is a monster light bucket, it is still reasonably portable for many adults due to its modular build. The heaviest components of the Stargate GoTo 20 are the 70 lb. mirror box and the 66 lb. base, and luckily, they are closest to the ground! All other components weigh less than 12 lb. each, and so the truss poles and upper cage are easily installed. With this kind of modularity, the unassembled Sky-Watcher StarGate 20 can fit in most any vehicle, and when you arrive at a star party, you will be everybody's best friend!

The GoTo version of the 20" 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. For more information on pointing accuracy, encoder resolution, and the motors see the specifications below.

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 quickly! 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. While you will receive a 12V DC power cord for the electronics, you will need to acquire your own power supply.

Sky-Watcher 20" 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
  • 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
  • Freedom Find dual encoders
  • SynScan with database of over 42,000 objects

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% above 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: 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: 12 lbs.
  • Truss Pole Weight: 2.6 lbs. each, 16 lbs. total
  • Mirror Box Weight: 70 lbs.
  • Dobsonian Base Weight: 66 lbs.
  • Fully Assembled Weight (with Counterweights): 164 lbs.