Telescope Data Center

Local Astronomical Catalog Formats

Standard ASCII and binary formats have been developed at the Smithsonian Astrophysical Observatory Telescope Data Center for astronomical catalogs which are to be plotted (or used as centers) by skymap, or searched (or used as search centers) by scat.

ASCII Catalogs

A simple ASCII catalog format was designed for ease of entry. Catalogs in this format can be plotted or used to designate map or search centers. Due to the existence of many formats for positional data, the simple structure has evolved over time, keeping its essential simplicy, but allowing more variation in the content and format of the position entries.

ASCII Catalog Examples

Binary Catalogs

Binary catalogs, which can be created from the aforementioned ASCII catalogs using starcat, are used to save space and make searches faster by presenting software with data in its internal representation. ASCII catalogs may be transferred between various computer architectures. The byte order in a binary catalog depends on the architecture on which it was written, though the catalog reading software can read either byte order. Catalogs available in this binary format include the SAO Catalog, the PPM Catalog, and the IRAS Point Source Catalog.

Last updated 23 August 2005 by Doug Mink,