Washington Double Star Catalog

The Washington Double Star Catalog is a database of double stars maintained by the USNO, that combines information from earlier such catalogs. It uses a Latin-alphabet code-abbreviation indicating the discoverer, such as STF for Friedrich Struve rather than the traditional Σ and in addition to the traditional designations, such stars are often cited using these codes (e.g., STF2740; for Σ2740; see Struve Catalogs) or with a WDS designation (WDS 20568+6134 or WDS J20568+6134). The WDS is an outgrowth of the IDS (Index Catalog of Visual Double Stars), developed and previously maintained by Lick Observatory.