Popular name for the Catalog of 3539 Zodiacal Stars published in 1940 by the Nautical Almanac Office of the US Naval Observatory. It lists the positions, magnitudes, spectral types, and proper motions of stars within 8° of the ecliptic, mostly brighter than magnitude 8.5, for epoch 1950.0. ZC numbers are still used for identifying stars that are occulted by the Moon.