Buckeyestargazer TriBahtinov Mask for Telescope Focus & Collimation Size:Tribahtinov-ESDOB1245 because traditional CMOS sensors often

because traditional CMOS sensors often do not have no amp-glow during the operation

Suitable for Retevis RT97 repeater

Dovetail includes 1/4″ screw hole

Designed for maximum contrast with steep gradients

Buckeyestargazer TriBahtinov Mask for Telescope Focus & Collimation Size:Tribahtinov-ESDOB1245 because traditional CMOS sensors oftenThe Buckeyestargazer TriBahtinov Mask combines the proven focusing precision of a traditional Bahtinov mask with the added ability to assess and fine tune collimation on telescopes with adjustable optics. Using a three zone diffraction design, the TriBahtinov pattern allows astrophotographers to achieve highly accurate focus while also identifying optical alignment errors, making it particularly valuable for SCT, RC, Maksutov, and other collimatable