About the DASCH Databases
The DASCH project data is currently organized in three MySQL databases: the scanner database, the photometry database, and the auxscanner database.
The scanner database contains the logbook information and keeps track of the scanning and processing of plates.
The photometry database stores the results of the photometry pipeline, which is implemented using tab-delimited ASCII Starbase Data Tables, and enables lightcurve plotting and statistical analysis of the photometry data.
The auxscanner database contains miscellaneous secondary data derived from other tables and files to improve overall processing performance.
global | Contains global constants, control variables, and a time stamp. |
locations | Contains observatory latitudes, longitudes, and elevations. |
ranges | Associates plate series numbers with observatory locations and the expected time type (UT, EST, SAST,...) . Handles duplicate plate numbers. |
series | Contains a list all of the telescopes and their characteristics |
classes | Contains a lists all known plate classes |
plates | Contains a list of all known plates. Contains a record of low resolution photographs of the plates and the plate jackets. Contains an overall plate quality flag. |
exposures | Contains a list of all exposures and their characteristics as derived from the logbooks |
catalog | Contains transcriptions of the plate stacks card catalog. This data is being replaced by more detailed data from the logbooks themselves. |
logbook | Contains transcriptions of logbook data |
logranges | Contains the ranges of plate numbers in each logbook volume. This table is used in the verification of logbook transcriptions. |
platerename | Contains a table of renamed plates (deprecated) |
scanPatterns | Contains a table of plate scan patterns executed by the digitizer. |
scanLocations | Contains a table of individual scan tile patterns for each scan pattern in the scanPatterns table |
scans | Contains a table of all plate scans executed by the digitizer |
mosaics | Contains a table of all mosaics generated from digitizer plate scans. This table contains World Coordinate Systems coefficients of each plate for the automated searches implemented by this website. |
fithistory | Contains a record of WCS fitting attempts (deprecated) |
astromfithistory | Contains the history of WCS fitting attempts after the transition to astrometry.net |
The database replaces a collection of tab-delimited ASCII Starbase Data Tables generated by the photometry pipeline. The intent of the photometry database is to provide rapid access to any lightcurve in the DASCH database. As currently designed, the photometry database contains the tables listed below. The primary spatial index into the database is a gsc_bin_index which divides the sky into 168,966,386 bins of height 1/64 degree in declination and approximately 1/64 degree in right ascension. This index is similar to the hierarchical triangle index developed for the SDSS, but optimized for rapid raster searches of the GSC2.3.2 star catalog. The illustration below shows how the tables are used to generate lightcurves.[[{"fid":"3654436","view_mode":"default","type":"media","attributes":{"height":"1056","width":"816","style":"width: 600px; height: 776px; float: left;","alt":"dataflow","class":"media-element file-default"}}]]
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photglobal | Contains global constants, control variables, and a time stamp. |
photversions | Contains version strings and identifiers in recognition of continuing development of the photometry pipeline. The versions are used to recognize and purge stale data from the other tables. |
photseries | Contains a copy of the series table index from the scanner database for more efficient MySQL queries |
stars | Contains the star index based on either location or GSC2.3.2 reference ID and the GSC2.3.2 magnitude and color. |
stars1 | Contains the star index based on either location or Kepler Input Catalog reference ID and the Kepler Input Catalog magnitude and color. |
stars2 | Contains the star index based on either location or APASS Catalog reference ID and APASS magnitude and color. |
photplates | Contains a list of all plates processed by the photometry pipeline and global plate parameters, such as the plate scale, mosaic size, and Sextractor THRESHOLD level. |
spatialbin | Contains derived parameters for the nine annular bins for each plate analyzed. These parameters include number of stars analyzed, limiting magnitude, upper limits, colorterm values, and bin rms. |
localbin | Contains derived parameters for the 50x50 grid of local correction bins for each plate analyzed. These parameters include altitude in the sky; plate extinction; local calibration correction, number of stars, and correction rms value; and astrometry error measurements. |
magnitudes | Contains values for each image on the plates. These values include GSC2.3.2 reference ID, plate coordinates, processing flags, magnitude, magnitude error, Heliocentric Julian date, and Sextractor shape parameters. This table is too large for efficient processing by MySQL and now consists of a series of binary files indexed by the gsc_bin_index. |
starsummary | Contains lightcurve statistics such as the number of points, DASCH magnitude and rms, clipped DASCH magnitude and rms, year range, and magnitude ranges. These statistics provide the basis for a search for interesting variable stars. |
starsummary1 | Contains statistics of stars in the stars1 table processed with the Kepler Input Catalog instead of the GSC2.3.2 catalog |
starsummary2 | Contains statistics of stars in the stars1 table processed with the APASS catalog instead of the GSC2.3.2 catalog |
calibration | Contains the relationship between SExtractor instrumental magnitude and GSC2.3.2 catalog magnitude for each plate and annular bin and the estimated RMS error for this relationship. |
calibration1 | Contains the relationship between SExtractor instrumental magnitude and Kepler Input Catalog magnitude for each plate and annular bin and the estimated RMS error for this relationship. |
calibration2 | Contains the relationship between SExtractor instrumental magnitude and APASS Catalog magnitude for each plate and annular bin and the estimated RMS error for this relationship. |
The auxscanner database contains tables which do not require periodic backup either because they are generated from text files or from other database tables.
Sort loglinks | Contains a linked list of all logbook page photographs for use by the logbook browser on this website. |
logindexnew | Contains the logbook volume and page number for all plates. Used by the logbook browser on this website. |
coverage | Contains a list of all plates indexed by one degree square regions of the sky. Used by the lightcurve generator. |
disks | Contains a list of all disks and raid arrays used by the DASCH project. |
variables | Contains the list of database variables listed in the Database Variables table below. Used for generation of VOTables |