Astrophysics (Index)About

point-spread function

(function describing an optical system's response to a point of light)

A point-spread function (PSF) is a description of the response of an optical system (such as a telescope) to incoming light from a point, consisting of a mathematical function describing the light-pattern expected on the focal plane, i.e., mapping relative position on the focal plane to the received EMR flux that would come from a point source. Such a function describing an Airy disk is an example. Theories have been developed regarding types of mathematical functions specific to particular aperture shapes (e.g., rectangles, slits, circles) and sizes: masks are sometimes used with telescopes producing various shapes because non-circular apertures in some cases reveal data obscured by circular apertures.

PSF subtraction (for point spread function subtraction) is a type of post-processing aimed at isolating the Airy disk of a specific star. Airy disks from images of lone stars taken with the same instrument are then used to help sort out the images of the stars with overlapping Airy disks.

Further reading:

Referenced by pages:
PSF fitting
speckle suppression