Henrietta Hill Swope (1902-1980) was an astronomer who worked at the Harvard College Observatory from 1928 to 1942. Her work focused on photometry and variable stars.
Within her first few years at the HCO, Swope’s studies of variable stars in a small area of the Milky Way enabled Harlow Shapley to identify it as the nucleus of the Milky Way galaxy, contradicting the previous belief that the Earth and Sun were at the center of the Galaxy.1 Next, Swope and Shapley embarked on an ambitious project to survey variable stars throughout the Milky Way and use them to trace the structure of the Galaxy. According to Cecilia Payne-Gaposchkin, Swope “evinced an extraordinary flair for discovering variable stars,”2 and by 1934, Swope was in charge of all of the Harvard programs on variable stars, which were “bearing fruit in enormous quantities.”3 By the end of her time at Harvard, Swope had found and charted more than 1,000 variable stars.4
While at the HCO, Swope also traveled to the Soviet Union in 1936 as part of the Harvard-MIT Eclipse Expedition to observe the solar eclipse of June 19, 1936. Her role was to use a six-inch telescope to photograph the solar corona in both plain and polarized light.5 A drawing in the official report of the expedition depicts Swope sitting atop a camel and “exchanging pleasantries” with their Russian hosts.6
Swope left the HCO in 1942 in order to help with projects related to military efforts in World War II. She spent a year on the staff of the MIT radiation laboratory, and in 1943, she was recruited to use her “genius in mathematics” to work on secret long-range navigation projects for the U.S. Department of the Navy.7 She helped to develop LORAN (Long Range Aid to Navigation), which allowed navigators to use radio signals from multiple locations to fix a precise position, and she was appointed head of the LORAN division at the Navy Hydrographic Office in Washington, D.C.8
In 1947, Swope became an associate astronomer at Barnard College, and in 1952, she moved to California to work as a research fellow at the Mt. Wilson and Mt. Palomar Observatories and as a faculty member at the California Institute of Technology. During this time, Swope’s research focused on determining the brightness and blinking periods of Cepheid variable stars, and the quality and precision of her work allowed other astronomers to use the stars as “yardsticks” with which to rapidly measure celestial distances.9 Swope used them to determine that the distance from earth to the Andromeda galaxy is 2.2 million light-years.10 She remained at the Mt. Wilson Observatory and CalTech until her retirement in 1968.11
Swope won the Annie Jump Cannon Award from the American Astronomical Society in 1968, among other honors and awards.12 She was also involved in supporting efforts for womens’ education. In 1938, she was one of five Barnard alumnae to participate in a nation-wide radio program entitled “Sending Girls to College, Why and How,”13 and in 1951, she and her parents donated $25,000 to establish a loan fund at Barnard meant to “assist in the education of young women, irrespective of color or creed.”14
Swope was born on October 26, 1902 in St. Louis, Missouri to Mary Hill Swope and Gerard Swope.15 Her father was a multimillionaire financier and president of General Electric, and her uncle, Herbert Bayard Swope, was a Pulitzer Prize-winning reporter and war correspondent.16 She was their only daughter and had four brothers. Despite her wealthy background, she was said to be modest, humble, and determined to work her own way up, with one exception: she drove “a convertible that would knock your eye out.”17 In a 1947 profile of Swope, a journalist said that “in her own way, she’s probably just as successful as her more famous father.”18 Swope died in November 1980 at the age of 78.19
Written by Elizabeth Coquillette, 2022
Selected Publications:
1. Swope, Henrietta H. “Two Hundred and Twenty-four New Variable Stars in Scorpio and Ophiuchus.” Harvard College Observatory Bulletin no. 857 (April 1928): 1-6. Bibcode: 1928BHarO.857….1S
2. Swope, Henrietta Hill and Harlow Shapley. “A peculiar variable with changing period and light curve.” Annals of the Astronomical Observatory of Harvard College vol. 105, no. 26 (1937): 499-507. Bibcode: 1937AnHar.105..499S
3. Swope, Henrietta Hill. “Variable stars in MWF 189.” Annals of the Astronomical Observatory of Harvard College vol. 109, no. 1 (1940). Bibcode: 1940AnHar.109….1S
4. Baade, W. and H. H. Swope. “The Draco system, a dwarf galaxy.” Astronomical Journal vol. 66 (September 1961): 300-347. Bibcode: 1961AJ…..66..300B
5. Baade, W. and H. H. Swope. “Variable star field 96’ south preceding the nucleus of the Andromeda galaxy.” Astronomical Journal, vol. 68 (1963): 435-470. Bibcode: 1963AJ…..68..435B
Citations:
1- “Astronomer Swope dies,” Chicago Tribune, November 30, 1980, p. B22.↩2- Cecilia Payne-Gaposchkin, Cecilia Payne Gaposchkin: An Autobiography and Other Recollections, ed. Katherine Haramundanis (Cambridge: Cambridge University Press, 1984), 170.↩
3- Ibid, 199.↩
4- Warren Hall, “The Rise of Henrietta Swope,” The Atlanta Constitution, May 11, 1947, p. SM16.↩
5- “Clouds Clear for the Harvard-M.I.T. Expedition in Russia,” The New York Times, June 19, 1936, p. 23.↩
6- Donald H. Menzel and Joseph C. Boyce, “Eclipse in Ak Bulak,” The Technology Review, Massachusetts Institute of Technology, vol. 39, 1 (November 1936).↩
7- Hall, “The Rise of Henrietta Swope.”↩
8- Alfred E. Clark, “Henrietta H. Swope, 78, Is Dead: Helped to Measure Variable Stars; Helped to Develop Loran,” New York Times, November 29, 1980, p. 28.↩
9- Lu Spehr, “A Star-Studded Career: All Work and No Play Suits Woman Astronomer,” Star News (Pasadena, CA), August 23, 1962, p. 19.↩
10- George Getze, “‘Beacons’ in Sky Help Figure Star Distances: Caltech Woman Astronomer Uses Young ‘Cepheids’ to Figure Andromeda Mileage,” Los Angeles Times, December 10, 1962, p. E7.↩
11- “9 CalTech Faculty Members Retire,” Pasadena Independent (Pasadena, CA), June 20, 1968, p. 31.↩
12- Clark, “Henrietta H. Swope, 78, Is Dead.”↩
13- “Broadcast to Open Barnard Jubilee: Dean Gildersleeve and Five Alumnae Will Speak on Radio Program Nov. 19: Listeners in 40 Cities,” New York Times, October 30, 1938, p. D7.↩
14- “Swopes, Jones Donate Money,” Barnard Bulletin (New York, NY), April 16, 1951, p. 2.↩
15- “Astronomer Swope dies.”↩
16- Hall, “The Rise of Henrietta Swope.”↩
17- Ibid.↩
18- Ibid.↩
19- Clark, “Henrietta H. Swope, 78, Is Dead.”↩