Historical+Data

Workshop on Historical TDA Data, Processing and Distribution Chairs:
 * Josh Grindlay (josh@head.cfa.harvard.edu)
 * Elizabeth Griffin (elizabeth.griffin@nrc.gc.ca)

Time Domain Astronomy (TDA) currently focuses on celestial variability in the present or in the most recent past (typically less than 20 years). But time-scales for variability embrace many orders of magnitude, and those much in excess of a century are not directly observable. For some 20-100 years of recent history, archives of astronomical plates containing images of the full sky or selected regions are accessible today, as are hundreds of thousands of stellar spectra, but will not be so indefinitely. One project (DASCH, at Harvard) has pioneered development of an ultra-high speed scanner and photometry pipeline that is now nearly ready to begin "production" scanning of the Harvard collection of some 550,000 plates covering the full sky; another (at the DAO, in BC) has commenced the on-line production of fully-reduced 1-D spectra from its archive of about 110,000 photographic spectra dating back to 1918.

The Workshop will explore (i) the major TDA science questions which can ONLY be tackled through electronic access to decade- or century-long baselines, (ii) the relative need for rapid access to both images (or thumbnails of regions), lightcurves of all separately detected objects, and associated catalogues, (iii) how to engage in a system of "alerts" from the historical TDA data to current (Catalina, PTF, PanSTARRS) and future (LSST) surveys, and more especially in reverse (from modern to historical data), iv) the database structures and rapid access tools that are needed to link the historical and modern TDA surveys, and v) how to collate TDA data encoded in spectra (e.g. velocity variations, spectral changes in eclipses or pulsations) across distributed archives. Participants should inform the workshop about relevant current or projected plans, and also of TDA results in the literature deriving from historic data.

Responding to the Symposium's objective of "exploring ways to harness technology and collaboration so as to meet newly-identified challenges in specified aspects of time-domain astronomy", the Workshop will consider the extent to which major historic datasets can be included in a linked international digital archive of images and spectra with common database structures and access/search tools.