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Stellar field analysis

Version : 1.0
Author(s) : Emiliano Diolaiti (
License : Free
Website :

Disk space required for installation is 2.40 Mb


A widget-based Graphical User Interface has been created, which allows one to use StarFinder without knowing IDL. The main widget which appears on the
screen is nothing more than an interface to call different widget-based applications, in order to perform various operations on the stellar field image. The main
widget defines a memory area to store some 'global' variables, whose name and meaning is listed below:

image: the stellar field
PSF: image of the Point Spread Function
noise: array of noise standard deviation for each image pixel
background: array, with an estimate of the background emission. Available after PSF extraction or stellar field analysis
detected stars: synthetic image, containing one replica of the PSF for each detected star in field. Available after stars detection
synthetic field: sum of background and detected stars

IDL users might wish to run the StarFinder routines directly from the IDL command line. Complete documentation on each module can be retrieved with the
IDL procedure doc_library.

The more interesting programs to analyze a stellar field are:

circ_mask: apply a circular mask to a 2D array, for instance the PSF
click_on_max: select local maxima by mouse click
compare_lists: find coincidences between two sets of points on a plane
crosses: mark interesting points in an image with crosses
display_image: display an image according to a set of options
fitstars: multi-component PSF-fitting of one or more stars
fwhm: compute the FWHM of a peak or stellar image
gaussian_noise_std: compute the standard deviation of normally distributed noise
halo_smooth: smooth the halo of a stellar image by means of a variable box size median filtering technique
image_background: estimate the background emission
image_core: extract the component connected to a specified starting position and above a pre-fixed threshold
image_model: create a synthetic image given by a sum of shifted scaled replicas of the PSF
match_coord: given two sets of coordinates on a plane, representing the same points in re-ciprocally translated and rotated
reference frames, map one of them onto the other
psf_extract: estimate the PSF by combination of a set of stars
repair_saturated: repair saturated stars
replace_pix: replace known bad pixels by local median
search_objects: search meaningful maxima
starfinder: stars detection, astrometry and photometry

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