Margaret Walton was born in Iron Hill, Maryland, on 27 January 1902, and died of congestive heart failure in Cambridge, Massachusetts, on 6 December 1995. The northern lights and Halley's comet in 1910 stimulated her early interest in astronomy. She graduated from Swarthmore College in January 1925, where L. J. Comrie encouraged her to seek employment at Harvard Observatory. There she worked for Annie J. Cannon, helping with the determination of magnitudes of stars in the Henry Draper Extension and became familiar with the HD system of spectral classification. Upon Miss Cannon's death (1941), Margaret classified stars for the second volume of the Henry Draper Extension, published in 1949 as the Annie J. Cannon Memorial Volume. This work was interrupted during World War II, when she worked at MIT in a Special Weapons Group.
Her first publication was in a Harvard Bulletin in 1927 on the distances of Cepheid variables. Until 1954, while she was associated with Harvard, she published some twenty papers on the photometry and spectral classes of variable stars. She was always ready to provide spectral classification information when needed, but support for large routine investigations waned after the war. Hence, when Leon Campbell, Recorder for the AAVSO, was about to retire in 1949, Harlow Shapley offered the job to Margaret Mayall, who gladly accepted.
Margaret's interest in variable stars crystallized when she spent the summers of 1925 and 1926 in Nantucket helping Margaret Harwood, Maria Mitchell Observatory Director, who was active in the discovery and determination of periods of variable stars. While on Nantucket Margaret Walton met R. Newton Mayall, a landscape architect and member of the American Association of Variable Star Observers. They were married in 1927. In 1928 she obtained her MA from Radcliffe College.
The AAVSO, founded in 1911 primarily by E. C. Pickering, Harvard Observatory director, was headquartered at Harvard, and Leon Campbell was the first Recorder. After Pickering's death the AAVSO established a fund in his memory, and by 1931 sufficient funds had been raised (about $100,000) to establish the post of Pickering Memorial Astronomer, which went to Campbell, and eventually to Mrs. Mayall. But after Shapley retired from the directorship in 1952, the new director evicted the AAVSO from its headquarters; and after ascertaining that only about $7000 of the Pickering Memorial Fund had been contributed by actual members of the AAVSO, decreed that henceforth only the annual income from the $7000 could be transferred from Harvard to the AAVSO. Only a person of staunch principles and great determination could have survived this colossal setback. For long periods 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. AAVSO Secretary Clinton B. Ford anonymously contributed substantial support, without which it is questionable that the AAVSO could have survived. Both Mayalls struggled steadfastly to prove that adversity could lead to greater independence than could ever have been achieved had the organization continued as a subsidiary of Harvard Observatory.
Deprived of her title as Pickering Memorial Astronomer at Harvard, Margaret's title was changed from Recorder to Director of the AAVSO. Surviving in crowded rented quarters from 1954 to 1986, the AAVSO, through the munificence of Clinton Ford, acquired its own headquarters, dedicated at its 75th anniversary, at last fulfilling Margaret's fondest dreams.
When a summer program was initiated in 1957 at the Maria Mitchell Observatory for student research on variable stars, Margaret welcomed their papers at the annual fall meetings of the AAVSO, publishing them in the AAVSO Bulletin. Thus she helped to launch many professional careers.
Many publications on variable stars have emanated from the AAVSO, steadily proliferating throughout Margaret's directorship and beyond. In addition, because of their interest in the encouragement of all amateur astronomers, the Mayalls wrote several popular books and updated Olcott's Field Book of the Skies and Webb's Celestial Objects for Common Telescopes. They also published two editions of their book, Sundials. Margaret retired in 1973.
In her last years, Margaret became almost totally blind. Yet until the end she maintained that cheerful disposition that was so characteristic of her. On 27 January 1996, a month after her death, the AAVSO held a memorial on what would have been her 94th birthday. Her accomplishments, with unmatched determination to overcome adversity, were warmly and deservedly eulogized. A Margaret W. Mayall Assistantship Fund has been established at the AAVSO in her honor.
Newton Mayall died six years before Margaret. They had no children. Margaret was a member of honorary and professional societies and received the Annie J. Cannon Award in 1958. Archival materials are chiefly at AAVSO Headquarters, 25 Birch Street, Cambridge, MA 02138.
Photo available in PDF version.