Transcription Project


Introducing, Project PHAEDRA! The John G. Wolbach Library has joined the team. We're working to digitize and transcribe notebooks from some of Harvard College Observatory's most famous women computers, including Henrietta Leavitt and Annie Jump Cannon. Upcoming projects include more of the Harvard College Observatory's historical work.

Interested in transcribing for the Astronomical Photographic Plate Collection or any of the Smithsonian's affiliates? We can always use volunteers and you can help from your home computer! Check out our projects and sign up to help here: Smithsonian Transcription Center  Thanks to these volunteers, we've completely transcribed all of the DASCH metadata from historic logbooks. Thank you! These transcriptions enable the DASCH project to continue scanning our 500,000 glass plate photographs and provide astronomical data for researchers around the world.


For press questions regarding the transcription efforts, please see the below write-up:


The Harvard College Observatory (HCO) houses the world’s largest collection of glass plate (mostly 8 x 10in) photo-negative images (~450,000 plates) and spectra (~100,000 plates) of the stars over the full sky (both northern and southern). The plates were taken by more than 20 Harvard telescopes in the US, Peru, S. Africa and others from 1885-1992. The story of the “women computers” who catalogued and analyzed those plates (primarily from 1890 – 1940), both the images for time variability of stars and spectra for the first classification of stars, is wonderfully told in Dava Sobel’s reecent book, The Glass Universe. A treasure trove of ~2400 notebooks and diaries of these women is now being systematically transcribed to be available online for public access by the Preserving Harvard’s Early Data and Research in Astronomy (PHaEDRA) project, conducted jointly by the HCO and the Smithsonian Astrophysical Observatory (SAO) which together constitute the Harvard-Smithsonian Center for Astrophysics. The ~450,000 imaging glass plates are being scanned and digitized at high resolution by the Digital Access to a Sky Century @ Harvard (DASCH) project (supported by NSF), now nearly halfway done, for both scientific and public access to the plate images and the derived brightness of every star on every plate to enable the first studies of stellar variability on timescales from ~1day to ~100 years.

DASCH and PHaEDRA have a symbiotic relationship: PHaEDRA shows how the women made their discoveries which transformed Astronomy, and DASCH extends these discoveries into the era of modern Astrophysics and Big Data in ways the women and the early HCO astronomers could not have imagined. Whereas most stars on most plates (a typical plate might contain 30,000 – 50,000 stars) were not measured or studied by the women, they will now all be available for study. Details of DASCH are available at and for PHaEDRA  at .