DASCH (Digital Access to a Sky Century @ Harvard)
The Harvard Astronomical Glass Plate Collection is an archive of roughly 500,000 images of the sky preserved on glass photographic plates, the way professional astronomers often captured images in the era before the dominance of digital technology. These plates are more than historical curiosities: they provide over a century’s worth of data that can be used by contemporary astronomers to trace how objects in the night sky change over periods from years to decades.
For that reason, researchers with the DASCH (Digital Access to a Sky Century @ Harvard) project are scanning the plates for digital storage and analysis. The process can also lead to new discoveries in old images, particularly of events that change over time, such as variable stars, novas, or black hole flares. The Harvard Astronomical Plate Collection is housed at the Harvard College Observatory (HCO), part of the Center for Astrophysics | Harvard & Smithsonian.