SKYWATCHER 300 BLACK DIAMOND REFLECTOR OTAOptimised for its prime focus photography, the telescope features a large 300mm aperture with a f 5 ratio, enabling you to view beautiful, scenic moment of the deep skies. The OTA also offers a dual speed 10: 1 Ratio Focuser for precise focal adjustments and would offer better results if used together with a Newtonian Coma Corrector. Needless to say, this Sky Watcher 300 1500 Photo Reflector OTA is remarkable in everything it offers. Sky Watcher Black