Archives of Photographic PLates for Astronomical USE

Contents of APPLAUSE DR2

Plate images

APPLAUSE provides two kinds of images of photographic plates: low-resolution preview images obtained before removing annotations from plates and high-resolution scans made after cleaning.

In total, DR2 contains 51517 scans of 42789 plates. 8728 plates have been scanned in two directions at a 90-degree angle.

Preview images are provided in either JPEG or PNG format. High-resolution scans have been made with Epson flatbed scanners at a resolution of 2400 dpi. An exception are Tartu plates, which have been scanned at a resolution of 1600 dpi. The scans are provided in FITS format, with a total size of 29 TB.

Access to images is provided through the query interface. If the result table contains links to images, the files can be downloaded either individually, or all files in selected columns or rows together. Also, for viewing plates and previews use the Europeana Viewer.

Images of logbooks, envelopes, etc

APPLAUSE provides JPEG images of digitized logbook pages, plate covers/envelopes, and other related material. As with plate images, the log-page images can be accessed through the query interface and through the Europeana Viewer.


The APPLAUSE database contains metadata about photographic plates and data extracted from digitized plates.

The source catalogue contains 2.59 billion extracted sources. The majority of sources have their positions (right ascension and declination) calibrated with the help of the Tycho-2 and UCAC4 catalogues. The database contains 1.407 billion sources with matched UCAC4 designations and 182 million sources with Tycho-2 designations.

Detailed information for each table you find here.