Photo essay: The untold history of women at Yerkes Observatory

NOV 07, 2023

Archival images highlight the work of female astronomers at the Wisconsin facility in the early 20th century.

DOI: 10.1063/PT.6.4.20231107a

Kristine Palmieri

Historical accounts of late 19th- and early 20th-century women in astronomy and astrophysics often focus on human computers, who performed tedious calculations to reduce the large amounts of data from positional observations, photographs, or spectrograms produced by men. Yet the stories of women at Yerkes Observatory challenge that traditional narrative.

New research on the history of the Williams Bay, Wisconsin, observatory has revealed that the women who worked there in the early 1900s were not, in fact, only or always computers. Many participated fully in the work of the observatory as graduate students, visiting researchers, or volunteer assistants. They observed with the telescopes, took photographs, collaborated with their male colleagues, wrote publications, and conducted independent research. Despite their accomplishments, they are little known today, even among astronomers and historians. You can learn more about some of those women in my article “They were astronomers ” in Physics Today’s November 2023 issue.

The photos in this gallery supplement the article with additional information about those astronomers and their work.

Mary Calvert operates the Kenwood 12-inch refracting telescope in 1926. Calvert is known for finishing her uncle E. E. Barnard’s *A Photographic Atlas of Selected Regions of the Milky Way*, which was published in 1927, four years after Barnard’s death. She also finished many other publications in Barnard’s name after his passing, receiving acknowledgement for her editorial work rather than for her authorship. But Calvert was an accomplished astronomer in her own right, a fact that was partially recognized by her 1927 promotion to assistant at the Yerkes Observatory. In 1934 she authored the *Atlas of the Northern Milky Way* with Frank Elmore Ross. (Courtesy of the University of Chicago Photographic Archive, apf6-01280, Hanna Holborn Gray Special Collections Research Center, University of Chicago Library.)

This photograph of the Sun’s corona was taken by Mary Calvert and E. E. Barnard during the Yerkes Observatory expedition to Green River, Wyoming, for the June 1918 total solar eclipse. They obtained the image through clouds using a 61.5-foot coelostat telescope with a 6-inch lens and a rotating mirror that allowed the astronomers to continuously monitor the path of the Sun during the eclipse. Because of its high quality, the image was used to produce slides that were employed for educational purposes across the country. (Courtesy of the University of Chicago Photographic Archive, apf6-02119, Hanna Holborn Gray Special Collections Research Center, University of Chicago Library.)

These images of the Sun by Mary Calvert illustrate the differences between a direct photograph (left) and a spectroheliogram (right). A spectroheliogram captures solar emissions at a single wavelength, characteristic of a specific atom or ion such as calcium. The spectroheliograph instrument was originally developed by Yerkes Observatory founder George Ellery Hale to explore the effects of magnetic fields. Although Hale became famous for his magnetic field research at Mount Wilson Observatory near Pasadena, California, the research team at Yerkes also continued a program of spectroheliograph photography and research. (Courtesy of the University of Chicago Photographic Archive, apf6-02306, Hanna Holborn Gray Special Collections Research Center, University of Chicago Library.)

Alice Hall Farnsworth (second row, fourth from left) worked closely with Yerkes astronomer John Parkhurst both as a PhD student and as a faculty member of Mount Holyoke College in Massachusetts. When Parkhurst died suddenly a few months before this August 1925 Yerkes staff photo, Farnsworth returned to Yerkes as an instructor to complete an unfinished publication on the photometry of 1550 stars. To return to Yerkes, Farnsworth withdrew her name from consideration for a Kellogg Fellowship at Lick Observatory in California that effectively had been promised to her. She would go on to hold the fellowship in 1930–31. Also pictured is Allie Vibert Douglas (far left), who earned her PhD in astrophysics from McGill University in 1926 for a thesis that utilized an extensive number of spectra from Yerkes. (Courtesy of the University of Chicago Photographic Archive, apf6-00444, Hanna Holborn Gray Special Collections Research Center, University of Chicago Library.)

Alice Hall Farnsworth studied this plate, which was made with a 6-inch Zeiss UV camera as part of a photometric investigation of 24 areas of the sky. Each area was one hour apart in right ascension at a declination of +45˚. A primary goal of the project, which Farnsworth took over after the death of her colleague John Parkhurst, was to find the photographic and photovisual magnitudes and the color indices of all the stars whose parallaxes and proper motions were to be studied with the Yerkes 40-inch reflecting telescope. The research was also designed to test the capabilities of that telescope and other Yerkes instruments: By comparing the stellar magnitudes obtained from each telescope, Farnsworth aimed to eliminate systematic errors in the instruments. Farnsworth had undertaken that kind of comparative work in her dissertation. (Courtesy of the Yerkes Glass Plate Collection, Hanna Holborn Gray Special Collections Research Center, University of Chicago Library.)

Harriet Parsons (right) earned both her master’s (1916) and doctorate (1921) degrees from the University of Chicago while working at Yerkes Observatory. She is pictured with Nora Johnson, who also worked at Yerkes before her sudden death at age 19 in 1916. Getting her degrees was not a straightforward task for Parsons. She wasn’t wealthy, and she had to cobble together the funds to support her studies from multiple sources. Tuition waivers, fellowships, and income from teaching at her undergraduate alma mater, Vassar College, in Poughkeepsie, New York, provided Parsons with the financial means to continue doing graduate work. (Courtesy of the University of Chicago Photographic Archive, apf6-01306, Hanna Holborn Gray Special Collections Research Center, University of Chicago Library.)

In her 1916 master’s thesis, Harriet Parsons provided the photovisual magnitudes of 111 stars in the Pleiades cluster, which she obtained through an analysis of 20 plates measured with a microphotometer. This plate was one of two taken with parallel wire grating placed over the objective lens of the telescope’s camera. The first step in the reduction of her measurements required Parsons to apply calibration corrections. She then converted the corrected scale readings into relative magnitudes. Finally, she reduced those relative magnitudes into absolute magnitudes on some definite scale. In two further tables she provided various notations from published sources and a comparison of her own work with magnitude determinations by other astronomers. (Courtesy of the Yerkes Glass Plate Collection, Hanna Holborn Gray Special Collections Research Center, University of Chicago Library.)

Evelyn Wornham Wickham (second row, far left) and Dorothy Block (first row, far right) were among the Yerkes Observatory staff members who attended the 23rd meeting of the American Astronomical Society in Ann Arbor, Michigan, in September 1919. Both Wickham and Block focused on stellar spectroscopy, work that was not gendered at Yerkes. When future Yerkes director Otto Struve arrived at the observatory in 1921, he was tasked with doing the same kind of work in stellar spectroscopy that Block had done before her departure. (Courtesy of the University of Chicago Photographic Archive, apf6-04473, Hanna Holborn Gray Special Collections Research Center, University of Chicago Library.)

Plate IB5800 was taken by Dorothy Block on 3 May 1920. The spectrogram of the binary star Epsilon Aurigae spans much of the 10 cm length of the plate, and the spectrum is approximately 1 mm thick. This plate and others that were measured by Block, Evelyn Wornham Wickham, and other members of the Yerkes staff—both men and women—helped inform a 1932 article by Edwin Frost, Otto Struve, and C. T. Elvey that contained detailed information about the star’s radial velocity and line intensities. The binary stellar system had attracted attention—and still does—because of its unusually long orbital period and eclipse duration, the evolutionary status of the supergiant primary star, and the invisibility of the secondary star. The research of the Yerkes team was at the cutting edge of astrophysics in the early 20th century. (Courtesy of the Yerkes Glass Plate Collection, Hanna Holborn Gray Special Collections Research Center, University of Chicago Library.)

Kristine Palmieri is a postdoctoral researcher at the rank of instructor with the Institute on the Formation of Knowledge at the University of Chicago. She is a cocurator of the exhibit Capturing the Stars: The Untold History of Women at Yerkes Observatory, which will be on display at the University of Chicago Library until 15 December 2023.