Harvard Revised catalogue

The Bright Star Catalogue, also known as the Yale Catalogue of Bright Stars or Yale Bright Star Catalogue, is a star catalogue that lists all stars of stellar magnitude 6.5 or brighter, which is roughly every star visible to the naked eye from Earth. The catalog contains 9,110 objects, of which 9,096 are stars, 10 are novae or supernovae, and 4 are non-stellar objects; the non-stellar objects are the globular clusters 47 Tucanae (designated HR 95) and NGC 2808 (HR 3671), and the open clusters NGC 2281 (HR 2496) and Messier 67 (HR 3515).

The catalogue is fixed in number of entries, but its data is maintained, and it is appended with a comments section about the objects that has been steadily enhanced since the first version in 1908. The version of 1991 was the fifth in order, a version that implied a considerable enhancement of the comments section, to a little more than the size of the catalogue itself. This most recent edition, in addition to several previous editions, was compiled and edited by Ellen Dorrit Hoffleit of Yale University.

Although the abbreviation for the catalog is BS or YBS, citations of stars indexed in the catalog use HR before the catalog number, after the catalog's 1908 predecessor, the Harvard Revised Photometry Catalogue produced by the Harvard College Observatory. The original Harvard Photometry was published in 1884 by Edward Charles Pickering, which contained about 4,000 stars. Following its release, Pickering promoted a broader stellar survey that would include stars from the southern celestial hemisphere. This photometry work was carried out by Solon I. Bailey between 1889 and 1891, leading to the publication of the Revised Harvard Photometry in 1908. The new catalogue contained stars down to magnitude 6.5 in both hemispheres. The work was then continued by John A. Parkhurst up through the 1920s.

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