Archives as Memories: Collaborations at The Observatories

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Astronomy & Cosmology
As I work with the historical glass plate images at the Carnegie Observatories, I frequently experience a sense of wonder at the order of the universe.


We televise rocket launches, celebrate astronomical discoveries, and delight in images of stars and worlds beyond our own. As Carnegie astronomer Allan Sandage once wrote, “astronomy is everybody’s second science ... it’s the general public’s escape.” As I work with the historical glass plate images at the Carnegie Observatories, I frequently experience a sense of wonder at the order of the universe. My experience cataloging Sandage’s own collection taught me that these objects are both beautiful images and important scientific data. Recently, however, I have also begun to see the collection as something else—a snapshot of the Observatories’ scientific culture and the researchers who have been drawn to this amazing place over the years.

Carnegie Observatories 2018 staff photo

Group portrait of Observatories' staff astronomers, taken 1939










After my internship ended, I was asked to stay on at the Carnegie Observatories and continue my work cataloging and investigating Sandage’s glass plate collection. As a result, I have learned a great deal about the history of the glass plates themselves over the last 11 months, including the processes for creating photographic images on glass, the science that these plates supported at the Observatories, and the historic telescopes at which the plates were made. I am also starting to learn about the many scientists whose work was entrusted to me by their inclusion in Sandage’s collection.

We are fortunate that Sandage participated in several oral histories in the 1970s and 1980s. As I read transcripts of these interviews, I gained a strong sense of Allan Sandage as a determined, yet funny, man who felt a great passion for his work and a sense of responsibility to continue the legacy of his scientific mentors.

“Just to take a 100-inch plate and have it in your hands was like touching the most-precious thing you could conceive of in the world...It’s hard now for me to really remember anything but the awe and the tremendous feeling of extreme opportunity that had been placed in my path,” said Sandage in 1977.

Photograph of drawer of plates in the Sandage collectionIn these histories, Sandage discussed his mentors and some of the other Observatories astronomers. This is how we know that Walter Baade was gregarious and full of entertaining tales about his colleagues and his work. Aside from Sandage’s interviews, there are few oral histories that can give us a glimpse of the Observatories’ culture in its early years. Fortunately, there are hints of the astronomers’ personal histories in the plate collection. 

Archiving can give you a sense of the people whose work you are handling. Over time, you cannot help but glean certain understandings of a person’s habits, preferences, and scientific approaches. For example, many astronomers made notations on their plates, but Edwin Hubble marked his extensively. To me, this is evidence that supports Sandage’s oral history statement that Hubble had the immense patience and a long-range point of view necessary to obtain valuable data off of even the lousiest plates. Conversely, Baade wrote extensively on his plate sleeves, making his research notes readily available to other scientists.

Picture of handwriting on an astronomical plate and on a plate sleeve.

In addition to the hints of personality that can be extracted from the plates and sleeves, I believe the actual inclusion of each astronomer’s work in the Sandage collection points to how their work was perceived by their peers. The number of plates from other astronomers that Sandage kept in his collection illustrates the data he valued and the skills he respected. For example, even before I began to understand the scope of Sandage’s scientific pursuits, I knew he must have collaborated frequently with Gustav Tammann, because I have discovered 48 of his plates in the collection (and counting). For Sandage to keep Tammann’s plates alongside the work of such pioneering astronomers as Hubble, Minkowski, Baade, and Humason demonstrated a high level of respect and appreciation for a younger astronomer that I found especially interesting. 

Portrait of Gustav Tammann, taken 1983

In researching the context of Tammann’s plates in the Sandage collection, I learned that Tammann was a Swiss Ph.D. student when he met Sandage at an international conference. Sandage believed that Tammann had the same kind of specialized skills in working with plates that Hubble had possessed—“This man was clearly unique and good”—and brought him to the Observatories to help with his work on Cepheids in the spiral galaxy NGC 2403. In his 1978 interview with historian Spencer Weart, Sandage stated that the Observatories paid Tammann’s salary for three years, but was unable to extend it beyond that period. To ensure Tammann was able to continue his work, Sandage applied for grants from the National Science Foundation for the first time in his career. The effort Sandage went to in order to keep Tammann on staff combined with the inclusion of Tammann’s plates in his collection, demonstrates how much he valued Tammann as a research assistant and fellow observer.

“Sandage and Tammann were lucky to find each other. Sandage knew the answer to his research questions, but Tammann had the patience necessary to work with the plates and painstakingly reduce and analyze the data. They remained close even after Tammann left the States, which was rare,” said Carnegie astronomer Barry Madore.

In addition to valuing the skills needed for measuring plates, Sandage also valued the process of observation. He told Weart there was indescribable scientific benefit to the direct operation of a telescope by an astronomer. Although the difficult work of maintaining focus on a guide star has been replaced today by computerized guidance systems, the Observatories’ telescopes are still often operated in “traditional mode” by the astronomers themselves. This means that the animated lunchtime and dinnertime conversations among astronomers working on the telescopes still occurs here and at our Las Campanas Observatory in Chile. 

Astronomers playing pool at Mount Wilson Observatory

But while we still have photographs and metadata from log entries that document collaborative efforts—not to mention the resulting papers—tangible data is largely a thing of the past. When astronomers come down from a mountaintop telescope today, they no longer carry boxes of photographic plates with them. This is a major part of what makes the Sandage collection so special—as more documents and records are born digital, tangible institutional holdings that document scientific processes and professional relationships are becoming more rare. 

The longer I work with this collection, the more I appreciate its unique place in the Observatories’ narrative. In the Sandage collection, visiting astronomers’ work is kept alongside plates made by Carnegie research assistants and staff, each of them drawn to Pasadena from across America and Europe. The Sandage collection is a reflection of the Observatories’ legacy as a research institution that attracts astronomers from all over the world and binds them together with the joy of discovery. 

Like Sandage, I am awed by the Observatories’ history, and I share his sense of loyalty to the people whose work we each inherited. Sandage’s collection is something beyond raw data and research notes—his collection is a memoir of the people and projects that were important to him. It is evidence of the camaraderie one can feel with one’s colleagues and the “elation at a construction he’s made that works.” As special collections like the Sandage collection become more rare, it is even more important to preserve the memories they hold and honor the history they represent. As an archivist, I am proud to conserve the legacy of the Observatories and, as ever, I look forward to more discoveries in the shelves.