A catalogue of positions and proper motions of 258 997 stars for epoch 1950.0, covering the whole sky down to about 10th magnitude, published by the Smithsonian Astrophysical Observatory in 1966. The original aim was to provide a dense net of stars which could be used as references for deriving positions of artificial satellites observed with wide-angle cameras. It has since been superseded by more accurate catalogues. An associated atlas was published in 1969.

http://cdsarc.u-strasbg.fr/viz-bin/Cat?I/131A Detailed description and full catalogue downloadable from the CDS.