Image data obtained with astronomical telescopes is subject to distortion from the instrument's and atmosphere's point-spread-function (PSF), which is both a mathematical and a physical representaion of how the image of a single point object (e.g. a star) is smeared over the optical plane of the instrument. The image of extended objects (e.g. planets) is a superposition of the PSF composited at every pixel of the image. The process of deconvolution can, in many cases, reverse the distorting effects of the PSF on both compact and extended objects. However, measuring a telescope's PSF is often a difficult or inconvenient process (or is not performed at all), so that estimates of the PSF extracted from the data itself are needed for deconvolution. In addition, the time-varying properties of the atmosphere also contribute to the overall PSF, making this extraction a dynamic process. This site presents some work in progress on the iterated extraction of telescope PSFs from astronomical image data.
© Sky Coyote 2005