Every Star Speaks for Itself: Williamina Fleming and the Work of the Harvard College Observatory
Maria C. McEachern
In collaboration with fellow John G. Wolbach Library colleagues:
Michael R. Blake, Amy L. Cohen, Christopher C. Erdmann and William L. Graves
To those with merely a cursory interest, the marks on the page may appear to be nothing more than jottings, possibly incomprehensible, in a dry tome which seems to consist mainly of lists of numbers. However, to those involved in its production and usage, Volume XXIV of the Annals of the Astronomical Observatory of Harvard College, in concert with its companion volumes, conveys the information which is the “skeletal framework of the science”1 while the hand-written annotations which appear on its pages reference not only a time of turmoil for the Harvard College Observatory but also the prodigious efforts of a devoted and utterly diligent astronomer Williamina Fleming.
The years 1877-1919 proved to be extraordinarily productive for Harvard College Observatory under the leadership of its entrepreneurial director Edward Charles Pickering. The routine usage of photography in astronomy was, at the time, groundbreaking. The photographic process could detect stars and other objects which were much fainter than those discernable by the human eye. Pickering’s ambitious plan was to photograph the entire sky and to systematically classify each star visible in the resulting images according to its apparent brightness. The more luminous stars were also to be catalogued by spectral type. When the light of a star is seen through a prism which is used in conjunction with a telescope, the cast image, the star’s spectrum, should indicate the makeup of the stellar object’s chemical component. In order to accomplish this massive undertaking, Pickering hired a corps of women workers who came to be known as “computers” and whose overwhelmingly successful teamwork became the embodiment of the “industrialization of astronomy”2 at the Harvard College Observatory. The systematic methods which had become the norm in factory work became standard in Pickering’s Observatory. “A great observatory should be as carefully organized and administered as a railroad,”3 Pickering once commented. In regard to economic considerations, he observed, “A great savings may be effectuated by employing unskilled and therefore inexpensive labor, of course, under careful supervision.”4
Overseeing the work of the computers, renowned for her disciplined methods, was Williamina Paton Stevens Fleming. She was known as “Mina” to friends and colleagues and had formerly been Pickering’s housekeeper. Fleming and her charges diligently inspected the images on the photographic plates and carefully calculated each star’s visual magnitude. The stellar objects were then classified and catalogued according to plan.
Additionally, Fleming was responsible for preparing and editing the massive amounts of data produced by the computers for publication in the Annals. Under her charge also fell the production, from original observation to data compilation and onward to final proofreading, of all other print materials issued by the Observatory such as its Circular. These publications were distributed to astronomical observatories and institutions of learning worldwide as well as to subscribing benefactors. Remarkably, in her years as an observer, 1881-1911, Fleming herself classified a total of 10,351 stellar spectra. She discovered more than 300 variable stars and 10 novae. Her inspections of the photographic plates also revealed 59 new gaseous nebulae, the discovery of 94 Wolf-Rayet stars and the initial identification of what would later come to be known as the Horsehead Nebula. Additionally, along with Pickering and astronomer Henry Norris Russell, she is credited with the discovery of the white dwarf-type star. In 1899, the title of Curator of Astronomical Photographs was bestowed upon Williamina thereby making her the first woman to be granted a formal appointment at Harvard. By 1911, the collection of photographic plates had grown to 200,000.
Fleming herself fully endorsed the photographic method of astronomical observation believing that the resulting images “must be considered more reliable, for in the case of a visual observer, you have simply his statement of how the object appeared at any given time as seen by him alone, while here you have a photograph in which every star speaks for itself”.5
In 1890, Volume XXIV of the Annals was published and contained information pertaining to position, magnitude and observational notations for 20,125 stars. Several years later, in 1894, an associate of the Observatory, Seth Carlo Chandler, publicly impugned the work. Chandler, a proponent of the tradition of observational astronomy who mistrusted the new astrophotography, published a letter in Astronomische Nachrichten claiming to have found “incongruities” in the material appearing in Volume XXIV which caused him to “distrust whether any of these observations are suitable for any precise measurement or critical purpose.”6 He listed 15 stars as “specimens of the discrepancies”.7 Pickering mounted a defense of the methodical and careful work done at the Observatory and, in turn, criticized Chandler’s inflammatory “inferences drawn from a few cases of exceptional difficulty”.8 He went on to point out that the greater mass of the Harvard data on stellar magnitude consistently compared precisely with that published by other astronomical institutions. On January 9, 1895, the New York Times declared: “Harvard’s Accuracy is Asserted; Prof. Pickering Defends the Astronomical Catalogue Against Certain Charges and Inferences”.9 The greater astronomical community worldwide dismissed Chandler’s charges and considered the work of the Harvard College Observatory to be exonerated.
Today, newly-obtained scientific data and any necessary corrections may be published electronically nearly instantaneously. Reconsideration determined that certain errors did exist within Volume XXIV of the Annals which Pickering deemed as “unimportant” and which affected “only the details of the observations”10 but not the final result. The published data for each star was based on a series of observations with the final figure having been derived by the computers who took into consideration the variable weather conditions and clarity of visibility at the time of each individual observation. Any existing errors in an individual observation would have altered the mean negligibly. Nevertheless, an “Errata” was published in Volume XXIII which appeared subsequently in 1899. Appropriately, the very same hand which had proven so intrinsic to the gathering of the data therein and was even directly responsible for its publication, that of Williamina Fleming, applied the written corrections to the physical copy existing within the Observatory Library and which is still available in the John G. Wolbach Library.
In recognition of her significant scientific achievements, the astronomical community applauded Fleming and her efforts by bestowing upon her several notable accolades. In 1906, she became the first American woman to be selected for Honorary Membership in the Royal Astronomical Society of London. Soon thereafter she was appointed as the only Honorary Fellow in Astronomy of Wellesley College. Also in 1906 she was elected as Honorary Member of the Sociedad Astrónomica de México. Just prior to her death, she was awarded its Guadelupe Almendaro Gold Medal for her work in the discovery of new stars.
In the Observatory’s 1912 Annual Report Pickering wrote, “By thirty years of continuous labor, and the expenditure of more than a million dollars, the Harvard Observatory has created a field of work which is not occupied elsewhere, in photometry, photography and spectroscopy.”11 In memoriam he went on to note the “severe loss” suffered by the Observatory when, on May 21, 1911, Williamina Fleming had passed away at the untimely age of 54 due to pneumonia. “Mrs. Fleming’s record as a discoverer of new stars, of stars of the fifth type, and of other objects having peculiar spectra, was unequalled. Her gifts as an administrative officer, especially in the preparation of the Annals, although seriously interfering with her scientific work, were of the greatest value to the Observatory.”12
1. Cecilia Payne-Gaposchkin, The Dyer’s Hand (n.p.: Privately printed, 1979): 51.
2. John Lankford and Ricky L. Slavings, “The Industrialization of American Astronomy, 1880-1940,” Physics Today 49 (1996): 34.
3. George Johnson, Miss Leavitt’s Stars: The Untold Story of the Woman Who Discovered How to Measure the Universe (New York: W.W. Norton, 2005): 18.
4. Ibid, p. 18.
5. M. Fleming, “A Field for Women’s Work in Astronomy,” Astronomy and Astrophysics 12 (1893): 685 – 686.
6. S.C. Chandler, “On the Observations of Variable Stars with the Meridian-Photometer of the Harvard College Observatory,” Astromische Nachrichten 134, no. 3214 (1894): 355.
7. Ibid, p. 357.
8. Edward C. Pickering, Forty-Ninth Annual Report of the Director of the Astronomical Observatory of Harvard College for Eleven Months Ending September 30, 1894 (Cambridge, Mass.: The University, 1894): 6.
9. “Harvard’s Accuracy is Asserted; Prof. Pickering Defends the Astronomical Catalogue Against Certain Charges and Inferences,” New York Times January 9, 1895. Proquest Historical Newspapers: The New York Times (1851-2007). http://search.proquest.com/docview/95244498/fulltextPDF/1311A0109AC5188DFAC/1?accountid=11311 (accessed 9 August 2011.)
10. Edward C. Pickering, “Errata,” Annals of the Astronomical Observatory of Harvard College XXIII, Part II (1899): 242.
11. Edward C. Pickering, Sixty-Sixth Annual Report of the Director of The Astronomical Observatory of Harvard College for the Year Ending September 30, 1911 (Cambridge, Mass.: The University, 1912): 3.
12. Ibid, p. 4.