eVscope TriBahtinov Mask

This TriBahtinov mask is an alternative to the standard Bahtinov mask used for Unistellar eVscope focusing. It is somewhat more difficult to use, but allows the user to perform coarse collimation in addition to focusing.

The focusing operation is similar to the Bahtinov mask. GoTo a bright star, add the mask, reduce the Gain/Exposure until six sets of three rays and a center dot are seen, and adjust focus until the best symmetry is obtained.

After focusing, collimation can be checked by rotating the mask until one set of three rays is aligned vertically or horizontally. The center ray of the set will be centered if the orthogonal collimation axis is aligned. Example: rotate mask until one set is aligned vertically. Adjust the horizontal collimation screw to center the middle vertical ray. Repeat for the other axis. This will achieve coarse collimation; perform fine collimation using actual Enhanced Vision images to center undistorted stars in the field.