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Paper: DASCH to Measure (and preserve) the Harvard Plates: Opening the ~100-year Time Domain Astronomy Window
Volume: 410, Preserving Astronomy's Photographic Legacy
Page: 101
Authors: Grindlay, J.; Tang, S.; Simcoe, R.; Laycock, S.; Los, E.; Mink, D.; Doane, A.; Champine, G.
Abstract: The temporal Universe is now possible to study on previously inaccessible timescales of days to decades, over a full century, with the planned full-digitization of the Harvard plate collection. The Digital Access to a Sky Century @ Harvard (DASCH) project has developed the world's highest-speed precision plate scanner and the required software to digitize the ~500,000 glass photographic plates (mostly 20 x 25 cm) that record images of the full sky taken by some 20 telescopes in both hemispheres over the period 1880 - 1985. These provide ~500-1000 measures of any object brighter than the plate limit (typically B ~14 - 17) with photometric accuracy from the digital image typically Δm ~0.10 - 0.15 mag, with the presently developed photometry pipeline and spatially-dependent calibration (using the Hubble Guide Star Catalog) for each plate. We provide an overview of DASCH, the processing, and example light curves that illustrate the power of this unique dataset and resource. Production scanning and serving on-line the entire ~1 PB database (both images and derived light curves) on spinning disk could be completed within ~3 - 5 y after funding (for scanner operations and database construction) is obtained.
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