Sky-Watcher Explorer-130PDS 130mm (5"") f/650 Parabolic Dual-Speed Newtonian Reflector, Optical Tube Assembly. The new Sky-Watcher EXPLORER-130PDS range of Newtonian Reflectors incorporate the same superb mirror-set as the Explorer-130P 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.Even better performance for astro-photography and visual use can be achieved when used in combination with Sky-Watcher's Newtonian coma corrector (Product Code 20233). Please note this is an Optical Tube Assembly only, mount and tripod are available separately.