Harvard Plate Collection Metcalf Telescope

Digital Access to a Sky Century @ Harvard
A New Look at the Temporal Universe

Current Status: 348,896 Plates Scanned 22,705,000,000 Magnitudes.

Celebration of the 350,000th scanned plate on May 30, 2019. Left Image: Helen Driscoll, Anne Callahan, Olivia Ambo, Melena Hogan. Right Image: Left to Right: Helen Driscoll, Olivia Ambo, Ed Los, Jamison Cloud, and Melena Hogan.

Primary Scientific Goals

The digitization of the Harvard Astronomical Plate Collection will provide the capability for systematic study of the sky on 100 year time scales.

DASCH will enable new Time Domain Astronomy (TDA) science, including:

Enabled by the DASCH scanner

Custom-designed scanner scans two 8 x 10 in plates or one 14 x 17 in plate into 11 micron pixels in only ~80 sec, which will allow ~400 plates/day so that full digitization could be finished by 2017 provided remaining needed telescope metadata (plate exposure date, time, etc.) is entered as can now be done through the Smithsonian Transcription site. Click here for ~2min movie (MS .wmv file) of scanner in action.

To yield lightcurves with ~0.1mag uncertainties over ~100y

Example lightcurve for an eclipsing binary in M44 is available here.


The DASCH project at Harvard is grateful for partial support from NSF grants AST-0407380, AST-0909073, and AST-1313370; which should be acknowledged in all papers making use of DASCH data.

We acknowledge the one-time gift of the Cornel and Cynthia K. Sarosdy Fund for DASCH, and thank Grzegorz Pojmanski of the ASAS project for providing some of the source code on which the DASCH web-interface is based.

The ongoing AAVSO Photometric All-Sky Survey (APASS) has improved DASCH photometric calibration and is funded by the Robert Martin Ayers Sciences Fund.