BAHTINOV FOCUSING MASK FOR EXPLORE SCIENTIFIC ED80CF OTA

thingiverse

Bahtinov focusing mask is a convenient astronomy tool to ease manual focusing of stars. The mask is placed in front of telescope's aperture. The telescope is pointed to a bright star. The mask produces 3 diffraction spikes. Two of them form an "X" shape, and another spike crosses it, forming a "Ж" shape. Adjusting telescope focus causes the central spike to move left or right, relative to the "X" spikes. When precise focus is achieved - the pattern becomes symmetrical. The 3D-printed bahtinov focusing mask is designed to fit in front of 120mm-OD dew-shield of Explore Scientific ED80CF refractor OTA, with 80 mm aperture, 480 mm focal length (f/6). Inner rim of the mask is fitted with 3 pieces of 1.8mm thick 20x50mm stick felt pads to fit snugly onto, and to prevent scratches on the dew-shield. The mask is printed from black ABS filament on a delta printer.