Chris,
I ran ZEMAX FFT and Huyghens analysis on the Bahtinov when it first came out, and had planned an article in Astronomy Technology Today on it. But my day job in optics has become very demanding in the last several months so I didn't get the article written.

Roger Ceragioli sent me your paper on your new innovation, and I wanted to get it up here and over in the ATM Forum.

This is my ZEMAX simulation of your Y-Mask, a much simpler and better alternative to the very complex Bahtinov mask. Your Y-Mask gives the same basic through-focus diffraction behavior as the Bahtinov, is FAR simpler to make, and gives an image that is at least one f-stop brighter.

Well done! This is a very good innovation. There is no reason to go to the trouble cutting all the slats in a Bahtinov with your new mask design.

For those not familiar with ZEMAX, the blue part of the pupil function on the left is where light comes through. Chris's new Y-shaped mask is an obstruction. The through-focus diffraction pattern behavior is not significantly changed by the introduction of a central obstruction.

Congratulations!
Mike