The Sky-Watcher Dobsonian Telescope 203mm/1200mm (8") hase a "paraboloidal" primary mirror to eliminate spherical aberration and a four-arm, secondary- mirror bracket with fine supports (0.5mm thick), to reduce diffraction spikes and light loss. In addition, this model include a 2" focuser with a 1.25" adapter, allowing the use of either eyepiece size.
Specifications: Optical Design Newtonian (Parabolic) Lens Material Diameter 203mm Focal Length 1200mm Secondary Mirror Diameter 47mm F/ratio F/5.9 Highest Practical Power 406x Faintest Stellar Magnitude 14.2 Resolving Power 0.56 Finderscope 9x50 Focuser diameter 2" with 1.25" adapter Diagonal Eyepiece(s) 1.25" Super 25 and 10 Mount Type Dobsonian Slow-motion Control Counterweight(s) Piggyback Bracket Accessory Tray Ground Board Diameter 52cm Ground Board Weight(s) Motor Drive Go-to Tube Weight 7.98Kgs