The Orion Sirius EQ-G GoTo 180mm Mak-Cass Telescope sets the standard for high-power performance and compact design. With 7" of aperture and that long focal length that Maksutov aficionados love, you'll get tack-sharp views and clearly defined photos with subtle detail and high contrast. And with GoTo motorized computer guidance you can automatically point the telescope to any of over 42,000 objects in the controller's database. The 180mm (7.1") optical system with its 2,700mm focal length (f/15) provides 44% more light grasp than the 150mm Mak, for brighter astro images and better resolution. It's the perfect combination of brightness, contrast, and high-power definition for planets, close double-stars, clusters, and well-defined deep-sky targets. The meniscus lens is fully multi-coated for maximum light transmission. The optical tube measures just 22" long and weighs less than16 lbs. The SynScan GoTo system employs two stepper motors to power the telescope to the object you select, putting it right in your eyepiece's field of view. The GoTo system will even take you on a guided sky tour of the best objects on any given night! The optical tube now comes with a 2" visual back and 2"-to-1.25" adapter, so you can use 2" or 1.25" accessories! What's more, the threads on which the 2" visual back attach are SCT (Schmidt-Cassegrain telescope) threads. So you can remove the visual back to thread on an optional SCT-specific diagonal or camera adapter designed for SCT threads. Also included are a 9x50 finder scope, 25mm (108x) Sirius Plossl 1.25" eyepiece, and a 90-degree 1.25" mirror star diagonal. The Sirius EQ-G mount includes an illuminated polar-axis scope, and two 11-lb. counterweights. The tripod is remarkably sturdy with 1.75"- diameter stainless steel legs and metal spreader plate. Requires external 12-volt power source or AC-to-DC adapter. Power, versatility, portability - if you're a serious big Mak fan then this one is for you!