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| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| Harvard Plate Stacks | 2/3 | https://en.wikipedia.org/wiki/Harvard_Plate_Stacks | reference | science, encyclopedia | 2026-05-05T04:38:51.318188+00:00 | kb-cron |
"My dear Mrs. Draper, Mr. Clark tells me that you are preparing to complete the work in which Dr. Draper was engaged, and my interest in this matter must be my excuse for addressing you regarding it. I need not state my satisfaction that you are taking this step, since it must be obvious that in no other way could you erect so lasting a monument to his memory." This would be the beginning of Anna Draper being the single largest benefactor to the Harvard College Observatory for the next three decades. Her funds and future endowment would back the creation, preservation, and housing of nearly 6000,000 glass plates and the core of the Harvard Plate Stacks collection, which would amount to a century of photographing the night sky. Her gift would not only include funds but also her and her husband's personal telescope. She would establish the Henry Draper Memorial, which would include both the creation of a physical photographic plate collection, as well as the study and publication of what is known as the Henry Draper Catalogue. Over 44 women would partake in the study, writing, and creation of the catalogue from 1886 until the final publication of Henry Draper Extension Charts in 1941. This would be part of the group of women known as the Harvard Computers or, more recently, referred to as the Women Astronomical Computers at Harvard. Nearly 200 women would work at the Harvard Plate Stacks during the century of the use of glass plate negatives, 1875–1975. Their individual and collective legacies shaped the way we understand the Universe. These impacts on said institution and field would be summarized nearly a century later by female astrophysicist, Dr. Dorrit Hoffleit, “there is hardly any branch of astronomy that has not benefited from the results of the Henry Draper Memorial. Without Mrs. Draper’s vision and generosity, one wonders how preeminent Harvard would have become.” Draper would also provide funds for the observatory to build three different buildings to house the Harvard Plate Stacks including its current home built in 1931. She would also separately establish the Henry Draper Medal, be a founder of the Mount Wilson Observatory, and establishing the Draper Collection of Cuneiform at the New York Public Library. This individual support would be compounded by other donations, including the estate of Uriah A. Boyden to establish a Southern Hemisphere Observatory, first called Boyden Station, and later Boyden Observatory. Originally stablished in Arequipa, Peru in 1889, the Observatory would be moved to Maselspoort near Bloemfontein, South Africa where it still exists and operates under the Physics Department of the University of the Free State (UFS) since 1976. Over 60% of the Plate Stacks collection would be made at these two locations. Uniquely among other astronomical glass plate collections, the Harvard Plate Stacks has an equal length history and even use of the same instruments to create plates of the northern and southern celestial hemispheres. This would lead to the creation of the "Harvard Map of the Sky" in 1917, the first photographic image of the entire visible universe. Printed on glass plate negatives from original plates deemed to be the best of each quadrant of the night sky, 55 glass plate negatives, which would later be expanded to 74 plates, would be copied using an interpositive process to create multiple copies of glass plate negatives for sale and distribution to other observatories, universities, and libraries. The first sets were offered around 1905 along with the "First Supplement to Catalogue of Variable Stars." According to Williamina Fleming's own published account, by October 1890, Harvard had photographed both the northern and southern hemispheres from Cambridge, MA and an earlier predecessor of the Boyden Observatory established on Mount Harvard near Chosica, Peru. This means that both the Harvard Plate Stacks contain the first photographic atlas of the visible universe, and even predates the much more well-known international collaboration and multidecade publication, Carte du Ciel. The scale and volume of creating photographic plates would go largely unchanged with only minor pauses or lower production during the two world wars. Other major donations for women would help shape the collection and advance the fields of Astronomy and astrophysics. Catherine Wolfe Bruce would fund the creation of a 24-in doublet telescope honoring her husband. This telescope would first be installed in Massachusetts to capture the northernmost stars, then moved to a purpose-built building at Boyden in Arequipa as its centerpiece. The Bruce telescope was the largest Astrograph at the time and would be used to create 30,000 glass plates. These plates, known as the A series, are the largest, measuring 14x17 inches, and are some of the farthest seeing plates in the collection. The Boyden Observatory was moved South Africa, enabled by a grant of $200,000 from the Rockefeller Foundation. Abby Aldrich Rockefeller funded the creation of a 60-in telescope.
== The Menzel Gap == In 1952, Donald Howard Menzel was appointed the director of the Harvard College Observatory. According to Dorrit Hoffleit, one of the first things he undertook in his new appointment was the systematic shuttering of the photographic program at Harvard. This included abandoning the Boyden Observatory, and the culling of thousands of plates from 1960-1965 through the creation of a Plate Stacks committee that excluded the voices of the curator of the collection, as well as those employed at the time as computers. This committee would meet and vote to destroy whole series of plates including experimental plates and early spectra plates. Because of Harvard's outsized role in the creation of astronomical glass plates even in this era, the resulting gap in astronomical data from the 1950s to the 1960s is referred to as the "Menzel Gap" by modern astrophysicists.