A Century of Sky: First Data Release from DASCH
Tuesday, May 14, 2013
News Feature

The Digital Access to a Sky Century @ Harvard (DASCH) project has made the first of 12 planned data releases. DASCH is digitally scanning the ~500,000 glass plate images covering the full sky and taken between 1885 and 1992. The first data set includes about 45,000 plates within 15 degrees latitude of the north galactic pole. It also includes test fields elsewhere: around the quasar 3C 273, the Beehive open cluster (M44), Baade's Window near the galactic center, the field of the Kepler planet-hunting mission, and the Large Magellanic Cloud.

DASCH has developed the precision high-speed scanner and software pipeline for processing the digital images for each plate. Photometry is calibrated to within 0.1 magnitude, and astrometry and light curves of all resolved objects on each plate are derived down to the local limiting magnitude (typically 12-17).

Production scanning of up to 400 plates per day is proceeding in galactic coordinates, from the north galactic pole down to a latitude of 15 degrees, then the south galactic pole up to a latitude of -15 degrees, and finally the galactic plane.

The full scanning and final data release can be finished by 2016 depending on continued support. DASCH gratefully acknowledges support from NSF grants AST0407380 and AST0909073.