Sky-Watcher Dobson 20" SynScan Go-To telescope (SW-1326)

Sky-Watcher is recognized as a global leader in telescope manufacturing, especially for Newtonian models on Dobsonian mounts. For many years, the company has focused on providing the highest quality optics, resulting in stunning views of the universe and countless positive reviews worldwide. With experience going back to 1990, Sky-Watcher Dobsonian telescopes are produced in an elegant, mature, and classic form, making them both affordable and accessible. While many competitors have tried to imitate them, no other brand matches Sky-Watcher in creating Dobsonians that are both optically outstanding and affordable.

This is the largest mass-produced visual telescope in the world.

The Sky-Watcher Dobson 20” is an ultra-light truss Dobsonian telescope with a parabolic mirror measuring 508 mm in diameter and an f/3.9 focal ratio. Despite its massive size, it is easy to transport because the telescope can be disassembled into smaller parts. Remarkably, one person can assemble this telescope and fit it into a sedan or hatchback for travel to dark-sky sites. The enormous 20-inch mirror provides breathtaking views, which are further enhanced when observing under truly dark skies, away from city lights and pollution.

Innovative Construction
Sky-Watcher has taken a new approach in designing the 20” Dobsonian. Inspired by the large Dobsonians popularized in the USA, the telescope features a thoughtfully engineered structure. During development, Sky-Watcher consulted with leading American experts such as Howie Glatter and Don Pensack. Instead of using heavy particle board, a numerically optimized lightweight frame was used for the primary mirror cage, with truss poles that unscrew into two sections for easier transport. The minimalist secondary cage keeps the center of gravity low, reducing the height of the base. The focuser height was also minimized, allowing most users to observe from ground level. For added stability, wide altitude bearings replace the standard ones, supporting heavy 2” eyepieces weighing up to 1 kg.

Go-To System
The telescope is equipped with a Go-To system that allows for automatic location and tracking of thousands of celestial objects. With precision stepper motors, observing comfort is dramatically improved. This drive system is a class above those found in other Dobsonians and matches the accuracy of professional-grade equatorial mounts like the EQ8. Objects can be selected via the hand controller, and electronic fine adjustments are possible. Dual-axis encoders and removable axis locks allow the telescope to be moved manually without losing tracking. Once a new object is selected, the telescope automatically follows its movement. The altitude axis uses a steel cable, and belt drives ensure minimal backlash.

This Go-To system is especially valuable for planetary imaging with a basic camera or specialized CCD cameras. The tracking also supports short-exposure deep-sky astrophotography and live high-definition video display for educational and demonstration purposes (with a suitable camera).

Note: No power supply is included; a separate AC or battery power supply must be purchased.

Advanced Optics
The parabolic primary mirror measures 508 mm in diameter with a focal length of 2000 mm. It is made from Pyrex using an innovative ribbed cone design to reduce weight and thermal mass. Combined with an open cell design, this allows quick thermal equilibration. The mirror is permanently mounted, which protects it, maintains collimation, and simplifies cleaning. Teflon bearings ensure smooth, easy manual movement—even at high magnifications above 300x.

Exceptional Observational Capabilities
The optical performance of this telescope is extraordinary. Its light-gathering power is more than five times greater than a standard 8-inch Dobsonian and over 56% greater than previous 16-inch models. The limiting magnitude is 9 magnitudes fainter than the naked eye, so stars and asteroids down to 17th magnitude are visible. Images are impressively bright and sharp, with nebulae, galaxies, and planets appearing spectacular under dark skies—often rivaling images seen online. Magnifications up to 500x are possible, limited only by atmospheric conditions.

New Possibilities in Large Dobsonians
This Sky-Watcher Dobsonian introduces a new standard with its combination of compact design, mobility, and enormous aperture. Anyone who has dreamed of a 16” Dobsonian but worried about size should look forward to this innovative, transportable 20” model.

Recommended Accessories
Due to the fast focal ratio (f/3.9), high-quality eyepieces that perform well with steep light cones are recommended. Excellent choices include Tele Vue Nagler, Delos, Ethos, Vixen LVW, Pentax XW, and Baader Morpheus. These complement the large mirror perfectly. A coma corrector is also advised for both astrophotography and visual use. UHC and other nebula filters, especially narrowband filters like OIII and H-beta, are strongly recommended—they isolate emission regions and greatly enhance views of planetary nebulae and faint emission nebulae.

Included Accessories

• Dobsonian mount

• Collimation eyepiece

• LET 28 mm eyepiece

• SP 10 mm eyepiece

• Covers for primary and secondary mirrors

• 2"/1.25" eyepiece adapter

• Retractable light shroud

• 9x50 finderscope

Specifications

Catalog Number: SW-1326
Optical Design: Newtonian
Mount Type: Dobsonian
Aperture: 508 mm
Focal Length: 2000 mm
Focal Ratio: f/3.9
Limiting Magnitude: 16.1
Maximum Useful Magnification: 1016x
Maximum Resolution (Rayleigh): 0.28"
Maximum Resolution (Dawes): 0.23"
Light Gathering Power: 5267x
Total Weight: 65 kg
Tube Length: 1700 mm
Mount Type: Dobsonian
Mount Drive: SynScan Go-To
Focuser Type: Crayford
Focuser Diameter: 2"
Focuser Micro-motion: Yes
Secondary Mirror Diameter: 136 mm
Electronics Warranty: 24 months
General Warranty: 60 months