BAHTINOV FOCUSING MASK FOR EXPLORE SCIENTIFIC ED80CF OTA

thingiverse

Bahtinov focusing masks ease manual star focusing with convenient astronomy tools. Place the mask in front of your telescope's aperture, then point it at a bright star. As you adjust the focus, three diffraction spikes will appear. Two of them form an "X" shape and another crosses over to create a "Z" shape. When the central spike moves left or right relative to these two spikes, you'll know the pattern is symmetrical - precise focus has been achieved. The 3D-printed bahtinov focusing mask was designed for telescopes with a 120mm outer diameter dew-shield and an 80mm aperture, such as the Explore Scientific ED80CF refractor OTA. This telescope has a focal length of 480mm (f/6). To ensure a snug fit on the dew-shield's inner rim without scratching it, three pieces of felt pads are attached to the mask. Each pad is 20x50mm and 1.8mm thick. The bahtinov focusing mask was printed from black ABS filament using a delta printer.