Mary Calvert: 20th June

Mary Ross Calvert (born 1884) was an American astronomical computer and astrophotographer. She started as her uncle Edward Emerson Barnard's assistant and ended publishing  their work that catalogued over 300 dark objects 

Mary Calvert operating the Kenwood 12-inch refractor telescope.  1926. 
Photographer George C. Blakslee.
The Hanna Holborn Gray Special Collections Research Center, The University of Chicago Library.

She was born in  Nashville, Tennessee, where her father and uncle ran a photography studio. 

She started work at Yerkes Observatory, Wisconsin, as assistant and computer for another uncle, Edward Emerson Barnard who was also professor of astronomy at the University of Chicago and known for his discovery of the high proper motion of Barnard's Star.

"A Photographic Atlas of Selected Regions of the Milky Way" by Barnard was completed after his death in 1923 by Edwin B. Frost.  Calvert had done the preliminary work under Frost's supervision and it was she who did the computations necessary to complete the tables, numbered and sketched in darker objects added annotation to the reference stars.

In 1923, when Barnard died, she became curator of the Yerkes photographic plate collection and a high-level assistant, until her retirement in 1946. After she retired from Yerkes she received no pension. She returned to Nashville, where she worked in her sister's photographic studio part-time.

She died in Nashville in 1974. 

Text and immages borrowed from Wikipedia and  University of Chicago Yerkes Observatory