Simplified Bahtinov focussing mask

A Bahtinov mask is a mask on a telescope that produces a line pattern that shows whether you are focussed well, and even shows if you are front or back focussed if not properly focussed. It requires a quite complicated mask, but almost the same effect can be achieved with 2 wires stuck to the aperture:


This results in a line pattern (Bahtinov results in dotted lines of 1st, 2nd etc order diffraction patterns):


But it still tells you where your current focus is (front, back or in focus):


One Response to “Simplified Bahtinov focussing mask”

  1. Almir Germano says:

    Good idea. I’ll try it in my next observing session. I do made my own Bahtinov for my Celestron C8, and it is well worth the trouble.

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