Archives of Photographic PLates for Astronomical USE

Welcome to the APPLAUSE archives

Example of a photographic plate. More sample images can be found in the image gallery. Access to all image material is also provided by the viewer

German astronomical observatories own considerable collection of photographic plates. While these observations lead to significant discoveries in the past, they are also of interest for scientists today and in the future. In particular, for the study of long-term variability of many types of stars, these measurements are of immense scientific value.

There are about 85000 plates in the archives of Hamburger Sternwarte, Dr. Karl Remeis-Sternwarte Bamberg, and Leibniz-Institut für Astrophysik Potsdam (AIP). The plates are digitized with high-resolution flatbed scanners. In addition, the corresponding plate envelopes and observation logbooks are digitized, and further metadata are entered into the database. The work is carried out within the project "Digitalisierung astronomischer Fotoplatten und ihre Integration in das internationale Virtual Observatory", which is funded by the DFG.

On this site, you can get access to the plate data that are processed so far. Please use the registration form to get a user account. Then you can submit SQL queries or fill search forms using the query interface. Without signing in, the query interface can be used as a guest user.

The APPLAUSE Data Release 4 (DR4) is the fourth release of archives of digitized photographic plates, along with metadata about scientific content the plates, digitized observation logbooks, and table data extracted from the images.

APPLAUSE DR4 contains:

  • images and metadata from 27 plate archives/collections from Hamburg, Bamberg, Potsdam, Tautenburg, Tartu and Vatican Observatory;
  • 125473 scans of 97703 photographic plates;
  • metadata for 94090 plates with a total of 139539 exposures;
  • 113960 images of logbook pages and plate covers;
  • 219 logbooks;
  • astrometric solutions for 68399 plates;
  • photometric calibration for 66328 plates;
  • 4.486 billion extracted sources (individual detections), of which 2.132 billion with matched Gaia EDR3 designations, 1.256 unique matches.

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 most precision and coverage, it is the reference catalog for most astrometry matching.

A classification - based on machine learning - of all source detections provides a likelihood for distinguishing between objects and artifacts.

Extracted source detections have their magnitudes calibrated, using the Gaia EDR3 catalogues as reference. The calibrated magnitudes together with observation times form light curves that can be extracted from the database.

The following sky coverage plots show the distribution of extracted source detections in the sky. It can be seen that with the addition of the Northern Sky catalog from Bamberg, the whole sky is covered more evenly (compared to DR3 of APPLAUSE), there are now even more observations from the Northern sky.

Time coverage is illustrated in the following figure. The oldest scanned plate in DR4 is from 1893, belonging to the Potsdam Carte du Ciel archive. The youngest plate is from 1998, obtained with the ESO 1-metre Schmidt telescope at La Silla, Chile.


If you make use of the APPLAUSE data please cite the the appropriate acknowledgements for the various data releases:


June 30th, 2022 APPLAUSE Data Release 4 published

Data Release 4 (DR4) was published on June 30, 2022. It contains images and data from the Bamberg, Hamburg, Potsdam, Tautenburg, Tartu and Vatican Observatory plate collections. 125473 scans of 97703 photographic plates; DR4 contains 125473 scans of 97703 photographic plates. All material of former data releases is included (execpt the Einsteinturm plates, which are published as DR3s). Additionally, 9113960 images of logbook pages and plate covers; 219 logbooks are available. More than 4.486 billion extracted sources (individual detections), of which 2.132 billion have matched Gaia EDR3 designations, with 1.256 billion unique matches.

More on DR4 you find at Data Release 4. For each of the 27 plate archives/collections of DR4 coverage plots are provided.

Also: with DR4 we use a very much improved version of Daiquiri software which provides now support for IVOA protocols and extended access methods via datalink. A full support for ADQL and TAP, and export of selected data into various forms (VO Table, CSV, FITS) is built in.

Compliance with the FAIR principles enhanced by an improved OAI-PMH API and enhanced metadata schema (DataCite, IVOA, Dublin Core), enabling other science communities to better access the metadata with their usual methods.

March 08th, 2019 Large surveys with small telescopes

The conference program is ready, and it's a dense sequence of talks from 09:00h to 18:00h each of the three days.

Conference Progam

The talks and posters are published on this Conference material .

October 24th, 2018 APPLAUSE Data Release 3 published

Data Release 3 (DR3) was published on October 24, 2018. It contains images and data from the Bamberg, Hamburg, Potsdam, Tautenburg and Tartu plate collections. DR3 contains 101138 scans of 70276 photographic plates. All material of former data releases is included. Additionally, 96852 images of logbook pages and plate covers from 215 logbooks are available. More than 3.508 billion extracted sources, of which 2.065 billion have with matched UCAC4 designations, again adding a billion sources compared to DR2. Both astrometry and photometry were redone with improved accuracy. The lightcurve table of DR3 combines information from different tables for convenience. Different to DR2 we only include data from one scan, if there were more than one. More on DR3 you find at Data Release 3. For each of the 24 plate archives/collections of DR3 coverage plots are provided.

Also: with DR3 we use the new Daiquiri software which provides improved support for IVOA protocols and extended access methods. A full support for ADQL and TAP is built in now, and also support for Europeana and other sites with a OAI-PMH API.

October 24th, 2018 Large surveys with small telescopes

Large surveys with small telescopes -Past, Present, and Future (Astroplate III)
A conference on the uses of digitized photographic plates
Bamberg, 11. to 13. of March 2019
More information and registration: Conference site

February 29th, 2016 APPLAUSE Data Release 2 published

Data Release 2 (DR2) was published on February 29, 2016. It contains data from the Bamberg, Hamburg, Potsdam, and Tartu plate collections. DR2 contains 51517 scans of 42789 plates. All material of the former data release is included in the 58115 digital images of plate covers and logbook pages, 149 logbooks. With 2.59 billion extracted sources this data release extends the former catalogs by nearly a billion sources. The lightcurve table of DR2 is calibrated and provides additional photometric information for astronomical work with the data. The total size of the published files is 30 TB.

April 24th, 2015 APPLAUSE Data Release 1 published

The APPLAUSE Data Release 1 (DR1) contains digitized phtographic plates from the Bamberg, Hamburg and Potsdam observatories. Over 25 thousand plate scans and a catalogue of over 1.6 billion extracted sources are available to the astronomy community and to the public. The oldest published plates date back to 1909 and the newest are from 1976. The majority of plate scans include astrometric solutions, making it possible to match the historic observations with contemporary object catalogues.

Plates in DR1 cover 98.9% of the entire sky, as illustrated with the following image. In the image, North is up and areas with no data are shown in grey.

September 18th, 2014 APPLAUSE database updated

The APPLAUSE database received a major update this month: the underlying structure was renewed and a large batch of data was added. Currently the database contains metadata of 19017 plates and over 127 million extracted sources from 4887 scans.

The database and website is still in beta stage. We expect to have minor changes to the database structure, as we continue to improve our plate processing pipeline.

September 21st, 2013 Plate Archive presented at the annual AG meeting

The Plate Archive and the digitization project will be presented in two talks at the Annual Meeting of Astronomische Gesellschaft:

  • Taavi Tuvikene – High-mass stars in the digital archive of photographic plates (Splinter meeting D, September 24)
  • Heinz Edelmann – The Bamberg photographic plate archive – the digitization project (Splinter meeting A, September 24)

September 19th, 2013 Plate Archive launched!

The Plate Archive has been launched with a small set of data for demonstration purposes. As of September 18, 2013, there are 2399 plates inserted from the Potsdam Zeiss Triplet and Hamburg Large Schmidt Telescope collections. The source catalogue includes data from the Cygnus OB2 association and its surroundings.

More will come in the months ahead!