Sky-Watcher’s Stargate truss-tube Dobsonian telescopes offer serious aperture for those looking to sail farther into the depths of the cosmos in big – and even bigger – deep-sky-gobbling apertures of 18 and 20 inches. For those stepping up from the 12-inch instruments, the 18-inch Stargate captures more than twice the light, and for those graduating from the popular 16-inch Dobs, the 20-inch gains 56-percent more. Aperture is king, and these new Dobs deliver that … and more.
Like the option of full go-to performance. Imagine the ability to locate and track celestial objects with nearly half a meter of aperture. Crank up the power on galaxies, clusters and nebulae without the annoying distraction of constantly re-centering your target. Sky-Watcher’s SynScan system keeps any celestial target centered, while you soak up all those gloriously ancient photons
Both big apertures feature a fused conical primary mirror and a cellular secondary mirror, a dual-speed 2-inch Crayford style focuser, two-section truss poles for ultra-compact transport, and a minimalist, all-metal design.
The 18-inch Stargate Dobsonian has a focal ratio of f/4.1 (1900-mm focal length) and a 120-mm (minor axis) secondary mirror, both of which are crafted from Borosilicate and finished with 94-percent reflective aluminum coatings. And that fast focal ratio yields an eyepiece height at Zenith of just 74.5 inches. It weighs 129 pounds fully assembled.
The 20-inch Stargate’s primary mirror has a focal ratio of f/3.95 (2000-mm focal length) and a 134-mm minor axis secondary, both with the same 94-percent coatings as the 18-inch. Eyepiece height at Zenith is 79 inches, and it weighs 138 pounds fully assembled.
The 18-inch Stargate is priced at $5,999US and the 20-inch Stargate at $6999US. Both include two eyepieces, a 9×50 optical finder, three 2.3-pound counter weights, a shroud and captive truss clamps, Add full go-to to either for another $1000US, featuring Freedom Find, dual encoders (which allow you to move the telescope manually without compromising alignment) and SynScan with 42,000+ object data base.