Documentation for the machine-readable version of the Henry Draper Catalogue (edition 1985)

An updated, corrected and extended machine-readable version of the catalog is described. Published and unpublished errors discovered in the previous version was corrected; letters indicating supplemental stars in the BD have been moved to a new byte to distinguish them from double-star components; and the machine readable portion of The Henry Draper Extension (HDE) (HA 100) was converted to the same format as the main catalog, with additional data added as necessary.