(Catalog of 5,268 Standard Stars, 1950.0 Based on the Normal System N30)
(1950s catalog collecting proper motion data from older catalogs)
By N30 Catalog I refer to
Catalog of 5,268 Standard Stars, 1950.0 Based on the Normal System N30,
a catalog published in the 1950s.
It included proper motion indicated by the stars' observed
motion over a 30-year period, determined through analysis of older
catalogs (thus the term "N30").
It retains value for the astrometric data it preserves.