Skywatcher Explorer-150PDS (OTA) Parabolic Newtonian Reflector incorporates the same superb mirror-set as the Explorer-200P Black Diamond Series, but with two significant advantages. A Dual-Speed 10:1 ratio focuser is now included for excellent focusing precision. Also the tube length has been slightly shortened to optimise performance for prime-focus photography. It features High Quality Parabolic Primary Mirrors to eliminate spherical aberrations inherent in 'fast' focal length reflectors with spherical primary mirrors. The mirrors are parabolized to bring all the light rays to the same focal point to give sharp, constrasty images, which are full of detail. Even better performance for astro-photography and visual use can be achieved when used in combination with Sky-Watcher’s Newtonian coma corrector. Features: Skywatcher Explorer-200PDS (OTA) Parabolic Dual-Speed Newtonian Reflector Telescope  8x50 Finderscope  Parabolic Primary Mirror  0.5mm Ultra-Thin Secondary Mirror Supports  2" (50.8mm) Dual-Speed 10:1 Crayford Focuser  77% more Light-Gathering than 150mm  Optimized For Prime Focus Astro-Photography  Shortened Tube Length for Optimized Performance Specification: Skywatcher Explorer-200PDS (OTA) Parabolic Dual-Speed Newtonian Reflector Telescope  Manufactured: Skywatcher  Magnification (with eyepiece Supplied): x36  Highest Practical Power (Potential): x400  Diameter of Primary Mirror: 200mm  Eyepieces Supplied ( (2"/50.8mm): 28mm LET  Telescope Focal Length: 1000mm (f/5) Kit Contents: Skywatcher Explorer-200PDS (OTA) Newtonian Reflector Telescope 8x50 Finderscope 28mm (2"/50.8mm) Eyepieces User Operating Instructions Manual Manufacturers Warranty