The calibration database consists of a directory containing all reduced calibration
files needed by the GPI DRP, and associated software for indexing and accessing
the calibration files. The location of the calibration data directory is configured
upon system installation.
The index of available calibrations is maintained in a FITS bintable file called GPI_Calibs_DB.fits located in the calibrations directory.
(For convenience, a human-readable copy of this file is also saved, in plain text format. This can be used to quickly examine by eye its contents)
The index table contains a list of various keyword values
of the reduced calibration data that can be used by the calibration DB software to
assign appropriate calibration
How the Calibration Database Selects Which File to Return
Below is a list of the Criteria used to select the correct recipe to reduce a given type of calibration file. The values for the Type, Exposure Time, Data, Filter, and Prism are pulled from the image headers of the raw files.
Calibration File |
Criteria |
Dark |
Type, Exposure time, date |
Wavelength solution |
Type, Filter, Prism, Date |
Polarimetry spots cal |
Type, Filter, Prism, Date |
Master flat |
Type, Filter, Prism |
Bad pixel map |
Type, Date |
Plate scale & orientation |
Type, Date |
Spot locations |
Type, Filter, Prism, Date |
Grid ratio |
Type, Filter, Prism, Date |
Distortion |
Type, Date |
Flux conversion |
Type, Filter, Prism, Date |
Telluric transmission |
Type, Filter, Prism, Date |
Instrumental polarization |
Type, Filter, Prism, Date |
The rules for matching files are detailed here.
Maintaining the Calibration Database
For the most part, the calibration database software takes care of maintaining
itself in a fairly automatic manner. As new calibration files are reduced, the
DRP software updates in real-time the calibration database.
The calibration file index can be
re-created at any time if needed by pressing the ‘Rescan Calib. DB’ button in the
pipeline Status Console. For instance, if you want to copy or move calibration
files from one computer to another, on the destination computer you should
rescan the database and it will pick up any new files that were added.