Sky-Watcher Dobsonian 8 Inch What is a Dobsonian Telescope and why the Tension Control Handle? In the late 1970s, John Dobson popularized a simple, elegant design to carry a Newtonian reflector. The Dobsonian mounted telescope is popular among amateur astronomers and telescope makers because of its simplicity. It consists of a box which allows the telescope to pivot in altitude and swivel left and right in azimuth. The Dobsonian mount relies on smooth friction between the mount and telescope to hold the optical tube in position. If there is too much friction, the telescope is difficult to move to center an object in the field of view. If there is too little friction, the telescope will not stay in the right position. The Sky-Watcher Dobsonian 8 Inch includes Tension Control Handles (US Patent No. 6,940,642) that users can easily adjust to add or reduce tension, thereby increasing or decreasing the friction between the optical tube and the sideboard of the mount. By providing such a tension adjuster the telescope will hold its position even when unbalanced. With the setting just right, the optical tube is stationary when you need, but can still be moved smoothly as necessary to follow the motion of your target. When the tension adjuster is completely tightened it locks the optical tube in position. Like any Dobsonian, the SkyWatcher Dobsonian 8 Inch provides more light grasp for your money than any other telescope type. We are often asked, "What telescope is the best for an avid beginner?". Of course the answer depends on how you plan to use your telescope, but SkyWatcher Dobsonian 8 Inch would be right near the top of the list! Specifications Optical Design Newtonian (Parabolic) Diameter 203mm Focal Length 1200mm F/Ratio F/5.9 Highest Practical Power 406x Finder Scope 8x50 2" Crayford Style Focuser with 1.25" adapter Eyepieces: 1.25” Wide angle 12.5mm and 20mm Tube Weight 11kg Tube Dimensions 20.5cm x 112cm Shipping Weight 15+17 kg
