OS-II Catalog

This is the astronomical catalog of near-Earth stars collected during the Origins II Survey. The cataloging method is an extension of the Hubble and Hoyle Guide Star Catalog (GSC). The sky was divided into 38,148 small square regions – established by dividing the sides of each of the GSC sky regions in half. Each spherical square had later width of one degree and a vertical height of 1° 41´ 54.96". The regional squares are arranged so that 00001 is centered on α Ursæ Minoris, and Regional Square 38148 is centered at the South Pole. An example of an OS-II catalog entry is OSI 31553+2349A. The first series of digits is the sky region. The second series with the “+”is the serial number within that region. Multiple star systems further identify the stars within the system with a unique alphabetical letter assigned by relative brightness – brightest to dimmest.