268-313 mm ID PinPoint Telescope Focusing Mask

The PinPoint Telescope Focusing Mask makes it easy to reach sharp focus in mere moments. Also known as a Bahtinov mask, this helpful accessory attaches to the objective of your telescope, where the precision-cut slot in the mask produces a distinct, intersecting 3-line pattern once accurate focus is achieved. While primarily used by astrophotographers, a Bahtinov mask can also assist visual observers who want to quickly achieve a sharp focus before observing bright stars, star clusters, double stars, and other deep sky sights. 

This 268-313 mm ID PinPoint Focusing Mask easily attaches to telescopes with an outer diameter ranging from 268 mm to 313 mm (10.55" to 12.32") by using the three adjustable rubberized pegs with thumbscrews to clamp onto the outside of the optical tube. With the mask installed, locate a bright star and begin making small focus adjustments until a intersecting 3-line diffraction pattern is visible. Once you see the distinct pattern, you'll confidently know that razor sharp focus has been achieved.