A Fourier method for the determination of focus for telescopes with stars [IMA]

http://arxiv.org/abs/2201.12466


We introduce a Fourier method (Fm) for the determination of best focus for telescopes with stars. Our method fits a power function, that we will derive in this paper, to a set of images taken as a function of focuser position. The best focus position is where the power is maximum. Fm was first tested with small refractor and Schmidt-Cassegrain (SCT) telescopes. After the successful small telescope tests, we then tested Fm with a 2 m Ritchey-Chr\’etien-Coud\’e (RCC). Our tests show that Fm is immune to the problems inherent in the popular half-flux diameter method.

Read this paper on arXiv…

C. Tan and B. Schulz
Tue, 1 Feb 22
64/73

Comments: This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society (MNRAS) Published by Oxford University Press on behalf of the Royal Astronomical Society