Scanning-releasing the full-sky-century database to DASCH for TDA

This is the last stage of a NSF supported effort. The Digital Analysis of a Sky Century @ Harvard (DASCH) project is now fully ready with its hardware, software and personnel resource planning and full production scanning, processing and data distribution and archiving can begin. This final grant will bring the world's only full-century Time Domain Astrophysics (TDA) database and analysis tools on line for the full community to utilize as a key survey that complements current surveys (PTF, CRT and PS1) and provides long-term context for LSST. The high speed precision DASCH scanner (two 8 x 10in imaging plates digitized into 11μm pixels in 90 sec) and initial astrometry and photometry have now i) improved astrometry that allows multiple exposure plate solutions as well as initial astrometry essentially independent of what the plate jacket might have indicated, ii) improved photometry. We build the Pipeline and Database software and hardware to enable the original goal to scan and fully process ~400 plates/day, which would enable the full collection of ~450,000 direct imaging plates to be scanned and fully reduced, with rapid access to images (thumbnails), lightcurves , and data products on spinning disk. The present effort will finish the production scanning, overnight processing, and full data releases (DRs, in 10 installments) of the ~375,000 plates remaining. Although a single field (6o centered on M44, our first "development field") is now in the public domain, the limited coverage presents the novel TDA surveys that DASCH can do for discovery and study of rare classes of variables which require larger survey coverage.

DASCH incorporates students at every stage and a vigorous program of Public Outreach. This research will open the astronomical window of time variability on long timescales (months-100y) from currently existing, but inaccessible and barely-mined data. Digitization is the key and can now be done with our new ultra-high speed scanner and high speed processing and database. Accessing the past data complements present (e.g. PanSTARRS) and future temporal surveys (LSST). Opening this new temporal window has already revealed new phenomena; it will surely excite new students and the public at large.
This project will awaken the public awareness that the universe is not static. Evolution and change are the rule, not the exception. The impact on science education can be large: by showing on the project website segments of the "cosmic movie" of giant flares from quasars or stars, or the heart beat pulsations of Cepheid variables, students will better understand the excitement of current astronomy. Physical understanding of the dynamic universe is even more enticing than the immutable sky. The public website to be fully developed by this investigation will be fully accessible to the public and astronomical community. DASCH will have significant impact on the general drive to Temporal Surveys for a number of projects now in development. It makes available the truly unique dataset that only a century of sky coverage can provide.