Sky-Watcher Stargate 18" f/4.2 Truss-Tube AZ Dobsonian Telescope

BH #SK18STTD • MFR #S11900
Sky-Watcher
Sky-Watcher Stargate 18" f/4.2 Truss-Tube AZ Dobsonian Telescope
Key Features
  • Large 18" (457mm) Aperture
  • 1900mm Focal Length, f/4.2 Focal Ratio
  • Fused Borosilicate Primary Mirror
  • 2" Two-Speed Crayford-Style Focuser
With the extremely large light bucket users have come to expect from a Dob, the Sky-Watcher Stargate 18" f/4.2 Truss-Tube Dobsonian Telescope gives users exceptional performance with a low dollar-to-aperture cost. Proprietary aluminum mirror coatings ensure maximum reflectivity, and a fused conical parabolic primary mirror design allows for thinner mirror construction. This provides faster cooling and lighter weight while also correcting spherical aberration to eliminate distortion across the entire field of view, especially at the edges.
Special Order
Expected availability: 7-14 business days
$5,999.00

Sky-Watcher Stargate 18" f/4.2 Truss-Tube AZ Dobsonian Telescope


Jacob K., B&H Optics Expert

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Sky-Watcher Stargate Overview

  • 1Description
  • 2Optical Tube
  • 3Mount
  • 4Included Accessories

With the extremely large light bucket users have come to expect from a Dob, the Sky-Watcher Stargate 18" f/4.2 Truss-Tube Dobsonian Telescope gives users exceptional performance with a low dollar-to-aperture cost. Proprietary aluminum mirror coatings ensure maximum reflectivity, and a fused conical parabolic primary mirror design allows for thinner mirror construction. This provides faster cooling and lighter weight while also correcting spherical aberration to eliminate distortion across the entire field of view, especially at the edges.

This telescope's large 18" aperture draws in a tremendous amount of light to reveal awe-inspiring details of the Moon and planets. Deep-sky objects will be visible even for inexperienced observers and bright star clusters can be resolved to their core. Its f/4.2 focal ratio and dual-speed Crayford focuser make this an ideal choice for imaging. The fast focal ratio enables devices to capture images in less time than slower scopes, while the focusing mechanism gives it the ability to achieve tack-sharp focusing with zero backlash that rack-and-pinion focusers are generally unable to accomplish. This 2" focuser will accept larger eyepieces so users can enjoy a truly immersive visual experience and will ensure larger imaging sensors are completely covered.

Its truss-tube construction and simple assembly enable a virtually complete breakdown for easier transportation and storage, with an assembly time of less than 20 minutes. To help block stray peripheral light and internal reflected light, Sky-Watcher includes a ribbed fabric shroud that completely covers the open trusses, giving users the convenience of the truss system with the performance of traditional solid tubes. The rocker box weighs in at 62 pounds and provides a rock-steady observational platform with very low vibration.

Optical Tube

  • 18" (457.2mm) aperture
  • f/4.2 focal ratio
  • 1900mm effective focal length
  • Dobsonian reflector light path
  • Fused borosilicate mirror glass allows for thinner mirrors that reduce weight and increase cooling
  • Highly reflective aluminum mirror coatings
  • 120mm secondary mirror, 7% obstruction by area
  • Resolution: 0.31 (Rayleigh); 0.25 (Dawes)
  • Dual-speed Crayford-style focuser enables more precise focusing than conventional rack-and-pinion without backlash
  • Max eyepiece height: 74.5" (189.2 cm), when OTA is pointed at the zenith
  • Open truss tube design allows for easier breakdown and transportation, with reduced weight versus solid tubes

Mount

  • Manual alt-azimuth
  • Steel and Teflon azimuth and altitude bearings enable smooth movement with limited vibrations
  • Floor standing with adjustable feet for proper leveling
  • Included three 2.3-pound (1kg) counterweights enable precise balancing, especially when using accessories such as heavy eyepieces or imaging rigs
  • Weight: 129 pounds, fully assembled with counterweights

Included Accessories

    Eyepiece:
  • 1.25" 10mm eyepiece yields 190x power, accepts most 1.25" astronomical filters
  • 2" long eye relief 28mm eyepiece produces 68x magnification, accepts most 2" astronomical filters
  • 1.25" collimation eyepiece enables the user to properly collimate the primary and secondary mirrors
  • 2"-to-1.25" reducer adapter allows the use of smaller eyepieces and accessories in the larger drawtube
    Finder:
  • 9x magnification ensures a wide field of view for faster alignment and easier star-hopping navigation
  • Large 50mm objective enables it to resolve dimmer objects
    Shroud:
  • Covers the open portion of the truss assembly
  • Ribbed fabric absorbs internal reflected light
  • Blocks peripheral exterior and reflected interior light which can interfere with light transmission to the mirrors
  • Helps to produce higher contrast views and sharper images during astrophotography
UPC: 050234119009

Sky-Watcher Stargate Specs

Optical DesignDobsonian reflector
Aperture18" / 457.2mm
Focal Length1900 mm
Focal Ratiof/4.15
Eyepiece Barrel Diameter2"
1.25" with included adapter
DiagonalNone
Finderscope9 x 50
TripodNone
Mount TypeFloor-mounted manual alt-az
Power SourceNone
Optical Tube DimensionsHeight: 80.7" / 205.0 cm
Horizontal radius: 57.1" / 145.0 cm
Base diameter: 23.2" / 59.0 cm
WeightUpper Cage: 11.0 lb / 5.0 kg
Truss Poles: 16.0 lb / 7.3 kg, total; 2.6 lb / 1.2 kg, each
Mirror Box: 62.0 lb / 28.1 kg
Dobsonian Base: 40.0 lb / 18.1 kg
Fully Assembled: 129.0 lb / 58.5 kg, with weights
Packaging Info
Package Weight202.55 lb
Box Dimensions (LxWxH)42.3 x 38 x 29"
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