Abbr. for Astronomische Gesellschaft Katalog, a series of catalogues of star positions. AGK1 covered most of the sky, observed by meridian circles around the world; it was published between 1890 and 1954. AGK2 (1951–8) was a repetition of AGK1, with additional stars, from the north pole to −2° declination observed photographically from Hamburg and Bonn in about 1930. It contains 181 581 stars, mostly to about magnitude 9 plus some fainter stars. AGK2A (published 1943) contains positions of 13 747 reference stars for AGK2, mostly of 8th and 9th magnitudes, derived from meridian observations made from Germany and Pulkovo, Russia. AGK3 (published 1975) was a reobservation of AGK2; the prefix AGK was retained even though the catalogue was not published under the auspices of the Astronomische Gesellschaft. AGK3R contains the positions of 21 499 reference stars for AGK3, observed in an international programme from about a dozen observatories. See also Southern Reference Stars.

http://cdsarc.u-strasbg.fr/viz-bin/Cat?I/61B Detailed description and full catalogue downloadable from the CDS.