Uppsala General Catalogue

[1] The catalogue includes essentially all galaxies north of declination −02°30′ and to a limiting diameter of 1.0 arcminute or to a limiting apparent magnitude of 14.5.

The primary source of data is the blue prints of the Palomar Observatory Sky Survey (POSS).

The catalogue contains descriptions of the galaxies and their surrounding areas, plus conventional system classifications and position angles for flattened galaxies.

Galaxy diameters are included and the classifications and descriptions are given in such a way as to provide as accurate an account as possible of the appearance of the galaxies on the prints.

The catalogue was edited by Peter Nilson, at the time Doctor of Astronomy and a researcher at Uppsala, who had already published some essays about the history of his science; a couple of years later he left his career as a professional astronomer behind and became a full-time writer, novelist and essayist, although the relationship of humans to space and cosmology, and the history of science, remained powerful themes in his later writing.