ASTRONOMICAL CATALOGS, CHARTS, AND SURVEYS
More than 2,000 astronomical catalogs and data tables are in use. The older method of printing catalogs has been superceded by storing them on compact disks and as computer databases, which can be accessed over the Internet. Different catalogs have been compiled for different types of objects, parts of the sky, regions of the electromagnetic spectrum, and so forth. The ones listed here are particularly important because of their generality or frequency of use, or for historical reasons. ("Catalogue" is the UK spelling, "catalog" the American spelling. The version used here for any given work is that encountered most frequently in the literature.)