2026-10-06T06:24:11Zhttps://www.plate-archive.org/oai/oai:www.plate-archive.org:schemas/applause_dr42022-06-24schemas10.17876/plate/dr.4APPLAUSE DR4APPLAUSE ProjectEnke, HarryTuvikene, TaaviEScience@AIPAstronomyLeibniz Institute for Astrophysics Potsdam (AIP)<p>The APPLAUSE Data Release 4 contains metadata about photographic plates and data extracted from digitized plates.</p><p>The source catalogue contains 4.486 billion extracted sources. The majority of extracted sources have their positions (right ascension and declination) calibrated with the help of Gaia EDR3 catalogue. Since EDR3 is the current astrometric catalog with the higest precision and coverage, it is the reference catalog for most astrometry matching. The database contains 2.132 billion sources with matched Gaia EDR3 designations, 1.256 billion unique matches. </p><p>The APPLAUSE DR4 database is organised in 20 tables. </p><p>Along with the data we publish the 4.x version of the pyplate software which was used to process the scanned material.</p>2022-06-24CC0Dataset