Archives of Photographic PLates for Astronomical USE

Example Queries into the databases

The following use cases demonstrate how the APPLAUSE database and query interface and plot facilities can be used.

Calibrated light curve and phase diagram

In this example, light curve of the eclipsing binary star V466 Cyg is queried from the APPLAUSE DR3 database. By using the known orbital period, it is possible to create a phase diagram.

Plates by observer name

The plate catalogue in APPLAUSE DR3 is queried to get plate counts for most productive observers. It is also shown how to select plates by observer name and browse preview images of plates.

Air temperature vs time

The plate catalogue sometimes also contains air temperature measurements by the observers. These data are used to create the Potsdam-Telegrafenberg air temperature plot from 1909 until mid-1930s.

Example Queries into the databases

Most examples given below work all tables from DR1 through DR3. The are referring to DR3 tables, where appropriate. For queries into DR1 and DR2 tables, simply exchange the schema name (applause_dr1, applause_dr2).

For example, to select plates in the Zeiss Triplet series with archive_id=1, one may use the following query:

SELECT * FROM applause_dr3.plate WHERE archive_id=1

In general, a plate may have been exposed multiple times, so there may be more than one observation start time and end time involved. Multiple-exposure plates are very common in the Potsdam Zeiss Triplet series: there are roughly twice as many multiple-exposure plates than single-exposure ones, and the multiple-exposure plates have, on average, 3.2 exposures recorded on them. Multiple-exposure plates can be found in the database by using the numexp column in the plate table:

SELECT * FROM applause_dr3.plate WHERE numexp > 1

Due to multiple exposures, all data that are related to exposures, like observation times, sky coordinates and object names, are stored in the exposure table. Each exposure has a unique exposure_id number. The exposure table also has columns for plate_id and archive_id, so that exposures of specific plates can be queried. For example, the following query selects all exposures of the plate with plate_id=398:

SELECT * FROM applause_dr3.exposure WHERE plate_id=398

In APPLAUSE, high-resolution images of plates, whether digitized by a scanner or some other device, are called scans. Data on scans are stored in the scan table, where a row corresponds to a single plate scan and carries a unique scan_id number. Plates that have been scanned multiple times have multiple entries in the scan table. The following example demonstrates selecting all scans of the plate with plate_id=29874:

SELECT * FROM applause_dr3.scan WHERE plate_id=29874

Data on extracted sources are stored in the source table and the source_calib table. Each source is identified by the unique source_id number. The source table contains extracted (instrumental) values provided by the SExtractor software. Calibrated data, like sky coordinates and cross-references with the Tycho-2 and UCAC4 catalogues, are stored in the source_calib table. Please note that calibrated photometry is not available in the APPLAUSE DR1. The source table gives only extracted instrumental magnitudes and fluxes.

The following example joins the source, source_calib and exposure tables using source_id and plate_id to get a calibrated light curve of the star S Doradus (UCAC4 catalogue designation 104-010297):

SELECT e.year_mid,s.mag_auto
FROM applause_dr3.source_calib AS sc
JOIN applause_dr3.source AS s ON sc.source_id=s.source_id
JOIN applause_dr3.exposure AS e ON sc.plate_id=e.plate_id
WHERE sc.ucac4_id='104-010297'

Since the available magnitude values of a star for all plates is an often used query, we provide the lightcurve tables with all relevant values from the three tables for convenience.

DR1 raw lightcurve:
The S Dor light curve can be queried from the raw_lightcurve table. Because raw_lightcurve does not contain year_mid values, we use Julian dates, jd_mid, instead:

SELECT jd_mid,mag_auto
FROM applause_dr1.raw_lightcurve
WHERE ucac4_id='104-010297'
ORDER BY jd_mid;

DR2/DR3 calibrated lightcurve
The S Dor light curve can be queried from the DR2/DR3 lightcurve table.

SELECT year_mid,bmag,vmag,bmagerr,vmagerr,
FROM applause_dr3.lightcurve
WHERE ucac4_id='104-010297'
ORDER BY year_mid;