The stars are an eternal map of the imagination, imprinting their ancient light on the retinas of creatures as far back as we can see. Eyes evolved in response to the light of our Sun, a G-type main-sequence star. Is it any wonder that we have directed our eyes and minds back to the stars with curiosity and intent to ponder our most elemental questions?
At its quintessence, the Harvard Astronomical Photographic Glass Plate Collection is a vast compendium of the recorded light of suns from across our universe. The collection is a veritable time capsule; as survey of photographic materials from 1885 to 1992, as record of the light and position of stars, and as chronicled evidence of the rigorous observations made by women astronomers who marked their research notations onto the plates. These entangled stories—of suns, of photography, and of the women’s handwritten marks—are the literal elements comprising this print edition, both in subject and material.
In the late 1800s, The Harvard College Observatory (HCO) began to hire a small group of women, known as the Harvard Computers, to study and preserve the growing collection of glass plate negatives. At a time when women struggled for basic rights and freedoms—let alone roles within the sciences—the Harvard Computers would come to revolutionize the science of astronomy and astrophysics through their discovery, study, and cataloging of hundreds of thousands of stars, deep sky objects and astronomical phenomena. Their work centered around the photographic glass plate negatives that were part of an astonishing effort by Harvard to photographically document and map the entirety of the night sky. Of the more than 550,000 glass plate negatives in the collection, untold thousands were directly annotated with research-based drawings on the glassy side of the plate by the many hands of the Harvard Computers.
Of the 141 women computers who are currently known to have worked at the HCO from 1881 to the 1950s, a small number are revered for their immense contributions to astronomy and astrophysics. Several of these more well-known women are thought to have marked plates within the Tracing Luminaries print edition. Williamina Fleming (b. 1857) who began her career at Harvard as the Observatory Director’s housekeeper, was one of the first women officially hired as a computer. In addition to working on spectra and dwarf stars, Fleming developed a classification of stars based on their hydrogen content. She also discovered 310 variable stars, 10 novae, and 59 nebulae, including the famous Horsehead Nebula. Henrietta Swan Leavitt (b. 1868) was a graduate of Radcliffe College and worked primarily on cataloging the brightness of stars. Her discovery and resulting famous paper studying 1777 variables in the Small & Large Magellanic Clouds led her to discover the phenomenally significant period-luminosity relationship of certain variable stars (two plates involved in her research are included in this print edition). Now known as Leavitt’s Law, this breakthrough established a standard candle with which to push the boundaries of parallax and triangulation to measure the great distances across space. Her research provided astronomers a path to measure the width of The Milky Way, to understand there were other galaxies beyond our own, and to see that the universe as a whole is expanding. Leavitt’s work has continued to have far-reaching impacts on astronomy and space activities today. Lesser-known Sylvia Mussells Lindsay (b. circa early 1900s) was an assistant astronomer at HCO in the 1930s, and in 1937 she discovered the first dwarf galaxy, known as the Sculptor Dwarf Galaxy (although the credit for her discovery is often given to Harvard’s then Director, Harlow Shapley).
As I write, the entire collection of glass plates is being scanned by the Harvard-Smithsonian Center for Astrophysics. Their project, Digital Access to a Sky Century at Harvard (DASCH) has been digitizing the plates since 2005 to produce photometry of the entire sky for the study of time domain astronomy and astrophysics. It is a significant and heroic effort that will allow researchers to track and compare variability in the brightness of stars over time. The data will be used to survey long-period variable stars, which have been more difficult to study given their prolonged cycles of dimming and brightening, and to examine variability that could yield new knowledge about quasars, novae, black holes, neutron stars, and perhaps even find novel types of stars or phenomena.
The contributions made by the women computers have continued to inform contemporary astronomy and astrophysics and will continue to do so. Thus, when I discovered that in order to achieve clean scans of the stars for the DASCH project, the glass negatives are wiped clean of all the women’s notations, the loss of these historic and intimate drawings was unimaginable. Their marks are depictions of the very moments of their imagination, innovation, and exacting inquiry of the stars. These glass plates are imbued with both tangible and intangible significance. The rich historic data of the stars captured on the photographic emulsion and the collection’s continued import in contemporary astronomical research are inseparable from the historical inked ephemera illustrating human exploration and knowledge seeking, our longing to learn the stars, and the people who carried that vision to us.
At the time I learned of this in June 2019, approximately 425,000 plates had already been scanned, and all written markings had been removed. Despite the fact that every plate with notations was photographically documented before being wiped, and even though a small group of around 600 marked glass plates depicting significant research and discoveries by the Harvard Computers were set aside and preserved intact for posterity, it remains difficult to comprehend that the lion’s share of the women’s actual, physical, hand-inked marks have been erased forever. This unfathomable erasure of the women’s work immediately compelled me to respond, by preserving some of their notations through art and poetically returning their lost marks to the stars once again.
Tracing Luminaries is a portfolio of six intaglio prints each depicting notations derived from a unique astronomical glass plate negative that was marked by the Harvard Computers and erased by the DASCH project. Working with the digital documentation imagery produced by DASCH to photographically preserve the notations prior to erasing them, Island Press and I digitally removed the stars from the image so that only the women’s notations remained. The notations were then laser engraved into cast acrylic plates that were subsequently inked with transparent base and printed onto a direct starlight-exposed cyanotype chine collé, which is bonded to Hahnemühle Copperplate backing paper. The process leaves the women’s marks embossed and once the transparent base is partially dry, each raised mark is hand gilded with 24 karat gold leaf.
In my lifetime, science has confirmed the remarkable epiphany that “we are made of star stuff,” a topic that is deeply embedded in all my work over the last 10 years. Most often attributed to Carl Sagan, the concepts and indeed the words themselves were proffered much earlier by a handful of scientists dating back to the early 20th century, including HCO Director, Harlow Shapley, who in 1929 in a New York Times interview is quoted as saying, “We are made of the same stuff as the stars, so when we study astronomy we are in a way only investigating our remote ancestry and our place in the universe of star stuff. Our very bodies consist of the same chemical elements found in the most distant nebulae, and our activities are guided by the same universal rules.”
This has key relevance as I consider the materiality of the photographic glass plate collection and its many handwritten notations. In the deep investigative work of the Harvard Computers, they were gazing into a veritable cosmic looking glass. In notating the plates, they were inscribing a kind of origin story: the chronicle of the incredible linkup of the stellar cosmochemistry and processes, which coalesced to a moment in time when a human being had the knowledge and tools to reflect on the formation of those stars. These inky stellar drawings are the literal and poetic realization of the human hand touching the stars.
My effort to return the women’s hand drawn notations to the stars began with the realization that I could not simply put them back together with the photograph of the stars from which they originated—this, of course, could be done digitally as DASCH maintains the digital documentation of both. Yet the estrangement and dissociation of the women’s marks from their stars is permanent, and this fact needed a prominent place within the artwork. So, I turned instead to the symbolic and literal meaning of star-made materials: photographic cyanotypes that have been exposed only to direct sunlight, and pure 24 karat gold. The language of these materials holds layers of meaning.
There is an elegant symmetry in thinking about using the photographic medium to capture the light of stars that are invisible to the unaided eye, for in the process of photography itself there is an invisibility to the image until it is developed and fixed. This latency is something that comes to mind again and again when considering the women’s marks being wiped from the plates—we know that the marks were there from the documentary photographs taken of them, but the marks themselves exist now only as the latent pressure of a human hand upon the photographic glass plate surface. You can no longer see the evidence of this embodied gravity, but it is there, somewhere, inside the glass.
In reflecting further upon such symmetries, it is also remarkable to consider that the composition of the photographic emulsion itself are elements born of stellar processes. The sole source of image illumination at the inception of the photographic medium in 1839 was our Sun, so you could say that the stars have been collaborating with the photographic medium since its inception. The photographic glass plate negatives in Harvard’s Sky Century recorded the light of myriad star-types. One could rightly muse that when the photographic emulsion—which contain elements that are born of dying stars—is then sensitized with the light of other stars during photographic exposure, the resulting image is, in every real sense, the stars meeting across time.
The photographic process used in this print edition is the cyanotype. Like any photographic print, this starlight recording holds within it the material meaning of the medium’s moniker: phos + graphê: to draw with light. In reflecting on the invention of the cyanotype process and the word “photography” itself, it is interesting to note that both are credited to astronomer John Herschel. Herschel invented the cyanotype as a way to copy his scientific notes from his astronomical research, and so this photographic process became for me a symbolically relevant medium to render the scientific notes of the Harvard Computers. The cyanotypes in this edition are made on Okuwara paper, where the paper’s surface is chemically sensitized with an emulsion and is then exposed entirely to natural sunlight—there is no intervening negative, only the pure light directly exposing the cyanotype-coated paper. Once developed, the image—which emerges as a surface of deep twilight blues—is simply a recording of our star’s light on a diaphanous fiber substrate.
The hand drawn marks are the material evidence of the women’s passion for and devotion to their research as much as they are evidence of the stars themselves. In imagining the women’s lifelong mark-making as the poetic gestures of exploration, we might also imagine that the women were among the first humans to touch the stars—tracing by hand, as they were, starlight across the cosmos. As gold is formed in the collision of neutron stars, it emerged as the perfect material with which to render and return their marks to the stars—by re-tracing their marks again, by hand, with star matter. This is a moment within the making of these prints that has profound conceptual import, for in the process of laying down the gold, the gilder must use a finger to gently press the gold leaf down along the form and flow of the women’s own handwriting. With just this thin auriferous sheet between the hand of the gilder and the marks of the women computers, a meeting occurs across time and among stars.
The entanglement of these star-made materials alongside interwoven ideas of latency and presence, of human and cosmic timescales, and of elemental reciprocity has coalesced as a kind of alchemy throughout the making of this work. In this way, their marks—these interstellar drawings—once again become embodied fluid topographies, embedded by the gravity force of the press as it orbited the intaglio plate and paper, finally revealing the women’s marks as elevated. Then, the elemental form of pure gold coalesces with the embossed ink layer forming a material bond that renders the text as star matter—and raised, as it would be, above the print’s own horizon line; their marks become, once again, star-bound.
—Erika Blumenfeld, 2022
(This essay is printed on the interior pages of the Tracing Luminaries portfolio)
Tracing Luminaries is a new print edition by Erika Blumenfeld—a portfolio of 6 prints housed in a custom handmade folio in an edition of 8—made in collaboration with Island Press. Tracing Luminaries was featured in the August 2022 issue of National Geographic. You can order a copy directly from Nat Geo or click here to read the digital version.
Please feel free to download Island Press’ publication brochure, which includes a curatorial essay by Eric Lutz, Associate Curator of Prints, Drawings, and Photographs at the Saint Louis Art Museum. Blumenfeld recently presented Tracing Luminaries in a talk hosted by the Wolbach Library at the Harvard-Smithsonian Center for Astrophysics, you can click here to watch the recording.