The Point Spread Function variations inside width-field astronomical images

Presenter: Elena Anisimova

The Point Spread Function (PSF) of the astronomical imaging systems is usually approximated by Gaussian or Moffat function. For simplification, the astronomical imaging system is considered to be time and space invariant. It means, invariable PSF within exposed 2D image is supposed. If we consider real width-field imaging systems this presumption is not fulfilled. In terms of real systems we have to consider stronger optical aberrations (especially coma) in terms of greater distances from the center of the captured image. This fact impacts the efficiency of stellar astrometry and photometry algorithms, therefore the PSF variation information is needed to be known. In this paper, the first step to PSF changes assignment is provided: the Moffat function parameters (FWHM and the atmospheric scattering coefficient) dependence on the stellar object position is monitored.

Jan Bednář, Petr Páta