Editing Point spread function (section)

=== Astronomy ===
[[File:Hubble PSF with flawed optics.jpg|thumb|The point spread function of [[Hubble Space Telescope]]'s [[Wide Field and Planetary Camera|WFPC]] camera before corrections were applied to its optical system.]]

In [[observational astronomy]], the experimental determination of a PSF is often very straightforward due to the ample supply of point sources ([[star]]s or [[quasars]]). The form and source of the PSF may vary widely depending on the instrument and the context in which it is used.

For [[radio telescopes]] and [[Diffraction-limited system|diffraction-limited]] space [[telescopes]], the dominant terms in the PSF may be inferred from the configuration of the aperture in the [[Fourier domain]].  In practice, there may be multiple terms contributed by the various components in a complex optical system. A complete description of the PSF will also include diffusion of light (or photo-electrons) in the detector, as well as [[Spacecraft attitude control|tracking]] errors in the spacecraft or telescope.

For ground-based optical telescopes, atmospheric turbulence (known as [[astronomical seeing]]) dominates the contribution to the PSF. In high-resolution ground-based imaging, the PSF is often found to vary with position in the image (an effect called anisoplanatism). In ground-based [[adaptive optics]] systems, the PSF is a combination of the aperture of the system with residual uncorrected atmospheric terms.<ref>{{Cite web|url=http://www.telescope-optics.net/diffraction_image.htm|title=POINT SPREAD FUNCTION (PSF)|website=www.telescope-optics.net|access-date=2017-12-30}}</ref>