Siril Spectrophotometric Catalog extracted from Gaia DR3

This is an extract of the Gaia DR3 catalog optimized for spectrophotometric color calibration. The catalog is indexed at HEALpix level 8 and selects up to the 127 brightest sources in each level 8 HEALpixel, though in many HEALpixels the number is limited by the Gaia sources that have xp_sampled records available. However this strategy ensures an even density of stars, providing sufficient stars for color calibration while avoiding overpopulation of the catalog in densely populated regions of the sky.

This catalog is developed for use with the Siril 1.4 series.

The catalog is provided as 48 compressed data files, each covering a level 1 HEALpixel indicated by the final number in the filename. A sha256sum file is provided for each compressed data file and a single file containing the sha256sums of all of the uncompressed files is also provided for additional verification.

Since splitting the catalog into chunks means users can download only the parts they need, but mapping of HEALpixels to regions of the sky is not obvious, a python script will be made available through the siril-scripts git repository to download chunks covering specified areas.

This version 1.0.1 corrects an error in the original release that meant some level 8 healpixels were incorrectly assigned to chunks and resulted in incorrect parsing of some files.