Hello everyone, eXcalibrator is an aid for the astrophotographer to consistently obtain reasonably correct color in "pretty pictures." The program uses the SDSS or APASS database to identify stars in your image that should be white. eXcalibrator then computes color correction factors. With the addition of the APASS data, eXcalibrator has nearly full sky coverage in both the northern and southern hemisphere. The program can now maintain a running average of the results. With careful use, this can substitute for a formal image-train color calibration. If eXcalibrator fails to get a result, use the running average and adjust for altitude extinction. Some users have been annoyed by the limited file naming convention. eXcalibrator now uses any legal Windows file or folder name. And of course, eXcalibrator is still a freeware. Here's the webpage with the download links. http://bf-astro.com/eXcalibrator/excalibrator.htm Cheers, Bob http://bf-astro.com