DASCH is the project to digitize the Harvard College Observatory’s Astronomical Photographic Glass Plate Collection for scientific applications. This irreplaceable resource provides a means for systematic study of the sky on 100-year time scales.

This website provides technical information for scientific users of the DASCH data. You might wish to:

For anything to do with the plates besides using the DASCH data for astrophysical research, visit the Plate Stacks website.

2024 February 12: A misconfigured maintenance operation run on November 18, 2023 caused the DASCH lightcurve database to report seriously incomplete results. The problem was resolved on February 10, 2024. If you requested DASCH lightcurve data at any time between these two dates, you should re-fetch the data. Please see the full news item for full details.

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About the Plates

The Harvard College Observatory's Astronomical Photographic Glass Plate Collection (Plate Stacks) is the largest collection of its kind in the world. The core of the collection is over 550,000 glass plate negatives and spectral images, covering both the northern and southern hemispheres. The Harvard Plate Stacks make up over a century of irreplaceable scientific observations and represent the first full image of the visible Universe. Hundreds of women studied and curated the Harvard Plate Stacks while making discoveries of their own, but more often than not their work went unrecognized. The Center for Astrophysics is dedicated to understanding and undoing the erasure of these women’s contributions while advancing and enabling the creation of new knowledge using the Harvard Plate Stacks Collection. Visit the Plate Stacks website to learn more about this unique resource.

About the Project

The DASCH project has been a herculean effort spanning two decades. Learn more about it on the About DASCH page, and meet the people behind DASCH. See the Acknowledgments page for information about the supporters that have made DASCH possible.