Margaret Walton Mayall (Born Margaret Lyle Walton), (Jan 27, 1902 - Dec 6, 1995) was an American Astronomer and head of the American Association of Variable Star Observers (AAVSO) from 1949-1973.

Mayall started at Harvard in 1924, working with Annie Jump Cannon to classify spectra of faint stars and estimating brightness of cataloged stars. They worked together on the second volume of Cannon’s “spectral work”, until Cannon’s death in 1941. Mayall edited the work so it could be published as the The Henry Draper Extension-The Annie J. Cannon Memorial in 1949. During some of her summers, she worked with Margaret Harwood of the Maria Mitchell Observatory on Nantucket, where she gained an interest in studying variable stars.¹

In 1949, Harlow Shapley asked Mayall if she would be interested in taking over as Recorder of the AAVSO from Leon Campbell. At the time the association was “headquartered and run under the auspices of” the Harvard College Observatory (HCO). She agreed. When the AAVSO was removed from the HCO, Mayall’s position was altered to ‘Director’, and she was forced to find a new home and financial support for her now-independent association.² In an obituary for Mayall written by Dorrit Hoffleit, she states “Margaret worked tirelessly, without salary, always apparently cheerful and optimistic, striving to get grants to continue the work as it had originally been planned. In all this her husband strongly supported her”. The AAVSO would eventually come to stand on its own feet in new headquarters, and would go on to help launch many professional careers.³

Mayall was born in Iron Hill, Maryland on January 27th, 1902. She graduated from Swarthmore College in 1924 with a Bachelor's Degree in Mathematics, and from Radcliffe College–Harvard university with a Masters in Astronomy in 1928.⁴ While working on Nantucket, she met Robert Newton Mayall and the two married in 1927.⁵ They were involved with the Ernst Sundial Collection of Harvard, repairing and writing about the objects, as well as co-writing several books on making and using sundials and other subjects.⁶ Between 1943 and 1946 Mayall worked on the research staff of the Heat Research Laboratory, Special Weapons Group, MIT. Mayall was the recipient of the G. Bruce Blair Gold Medal from the Western Amateur Astronomers in 1957, and the Annie Jump Cannon Award from the American Astronomical Society in 1958.⁷ In 1982 a Minor Planet/Asteroid was named in honor of her and her husband, 3342 Fivesparks, named for their home in Cambridge.⁸

Margaret Mayall’s publications in the field of Astronomy from her time with the HCO can be found through the SAO/NASA Astrophysics Data System. The Henry Draper Catalog Extension, and Archives related to the Ernst Sundial Collection can be found through the John G. Wolbach Library, HOLLIS. Archives materials from Mayall's time with the AAVSO can now be found through the Harvard University Archives.

Written by Samantha Notick, 2022

Selected Publications:

1. Cannon, & Mayall, M. W. (1949). The Annie J. Cannon memorial volume of the Henry Draper extension [Charts]. The Observatory.
2. Mayall, & Mayall, Margaret W. (1938). Sundials : how to know, use, and make them. Hale, Cushman & Flint.
3.Mayall, & Mayall, Margaret W. (1949). Skyshooting : hunting the stars with your camera. Ronald Press Co.

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