This innovative focus mask concept was invented by Russian amateur astronomer Paul Bahtinov, and Kendrick is producing these masks with his permission.
The Bahtinov mask allows digital astrophotographers and visual observers to get razor sharp focus in seconds!
The difference in focuser position when a change in the diffraction pattern becomes visibly apparent is very small--typically a few tenths of a millimeter. The method is very fast and incredibly sensitive. There is no guessing when you are focused during times of poor to moderate seeing. Simply put the mask and the status of your focus will become immediately apparent.
The masks have a series of slots that create a unique diffraction pattern that can be used to quickly bring your telescope to focus with an absolute minimum of fuss.