Mary R. Calvert, American astronomer and author (d. 1974)
Mary Ross Calvert (June 20, 1884 – June 25, 1974) was an American astronomical computer and astrophotographer. She started as her uncle Edward Emerson Barnard's assistant and ended publishing his (and their) work that cataloged over 300 dark objects (dark nebulae) — primarily those that extinguish the most starlight reaching the earth lie between the bulk (inward local sector, central bulge, and other sectors of the Milky Way) thus between the Local Arm (Orion Arm) and the Sagittarius Arm. She went on to publish other photographic works on astronomy.