astronomical catalog

Astronomical catalogs, i.e., lists of observed phenomena (stars, galaxies, quasars, etc.) are assembled and enlarged for various purposes. Examples:

• Hipparchus's catalog from 2000 years ago but lost: stars and their magnitudes.
• Messier Catalog (M)
• New General Catalogue (NGC)
• Principal Galaxies Catalog (PGC)

Recent and current surveys often produce one or more associated catalogs, often using a survey-based designator for its object designators. Catalogs often aim to list certain characteristics of the objects, such as catalogs of photometry or proper motion of stars. In the past, catalogs were published as books, but more recently, online databases are common, sometimes with ongoing updates. Lists that can be thought of as short catalogs have been and still are included in published research papers. Some catalogs are designed to be sample data sets, i.e., representations of some particular type of object or source with a particular characteristic. In some cases, the selection is aimed at statistical studies.

Mock catalogs have been produced: artificial catalogs of realistic-but-nonexistent objects, to assist with modeling.

Star catalogs have a long history and are still being created, both in the study of the larger number of stars now observable with modern telescopes, and also for the purposes of navigation and time standards, (e.g., the USNO's NOMAD) and for assisting in aiming telescopes and recording the position of observed objects (e.g., the Guide Star Catalog).

See list of catalogs and list of survey/catalog indicators.