Fundamental Katalog (FK)
Fundamental Katalog (FK) is a series of fundamental catalogues published in Germany. The first, in 1879, provided reference positions for the Astronomische Gesellschaft Katalog. There followed the second FK (NFK) in 1907, FK3 in 1937-38, and FK4 in 1963. FK5, published in 1988, contained, like its predecessor, 1,535 stars, brighter than about magnitude 7.5, distributed in a roughly evenly across the entire sky. An extension to FK5, listing a further 3,117 stars, down to magnitude 9.5, appeared in 1991.