Bahtinov diffraction pattern not right

[Alan Snook]

Hi Folks,
Last night I put a Bahtinov mask on my Altair Astro 130EDT refractor. The diffraction pattern I am seeing at point of focus is not the expected cross with an intercept. Any suggestions on what the reason may be please?

• This topic was modified 1 hour, 49 minutes ago by Alan Snook.

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