INTEGRALPlanckGaiaPOLARCHEOPSEuclidATHENA
HEAVENSFACTCTALOFTSPICAJEM-EUSOXIPEeXTPTheseus
XRISMMAGBOUNDSMARTNet
ISDCCDCI
Cherenkov Telescope Array
What is a FITS data structure template ?
In preparation for the INTEGRAL gamma-ray satellite, the ISDC developed the concept of data structure templates to define the format of all data from INTEGRAL. Data structure templates are text (ASCII) files defining the exact structure of a set of FITS files and that can be used with a simple command to create corresponding empty FITS files. A template is analog to the plan to construct a shelf (an empty FITS file) to be filled by well defined objects (a set of data). Each template defines the format of one specific type of data set to be stored in a distinct extension of a FITS file
For INTEGRAL, the ISDC has defined and maintains more than 1300 different data structures that form a coherent data model for all instruments. A similar approach was also used for the ISDC development of the Level 1 data processing for the Low-Frequency Instrument (LFI) of the Planck satellite. The same scheme is now also used to define the FITS data format for the CTA project.
Basicly, there are only three distinct types of data structures. Data can either be organized in a table with a series of data columns or an image or a set of images forming a data cube. A third type of data structure are indices grouping together identical or different data structures in a single FITS file. The actual data for any kind of data structures is always complemented by metadata (FITS keywords) defining the context of the data acquisition (e.g. instrument configuration, date of observation, energy bands, etc.).
Please use the wiki page to discuss these templates.

Science Products - Templates

Name Description Version
Sky image (intensity, variance, significance, exposure,...) for given time interval (or phase bins) and energy band
List of detected sources
Source spectrum for a given time interval
Source lightcurve in a given energy band

Parameterized Events - Templates

Name Description Version
Parameters (e.g. Hillas or physical models of the showers) characterizing the images of the air showers in each telescope for each event.

Calibrated Data - Templates

Name Description Version
Images of the air showers in each telescope for each triggered event
Calibrated telescope housekeeping information

Calibrated Auxiliary Data - Templates

Name Description Version
Reconstructed telescope pointing information
Calibrated atmospheric transparency
Calibrated weather conditions
Hardware configuration
Hardware failure information
Calibrated timing information
Proposal information
Scheduling information
System stability information (e.g. trigger rate fluctuations)

Raw Data - Templates

Name Description Version
Raw pixel-by-pixel information (signal intensity in photo-electrons and pulse evolution) data for each of the triggered events as recorded by the camera pixels
Raw telescope trigger information
Raw telescope pointing information
Raw telescope housekeeping information (e.g. drive information)
Raw atmospheric monitoring information
Raw weather conditions monitoring information
Raw hardware (telescope, camera) configuration information
Raw absolute timing information
Raw TBD calibration information
Log book, exposure and observation report

Monte Carlo - Templates

Name Description Version
TBD library of Monte Carlo simulated atmospheric showers
TBD library of telescope simulator parameters

Calibration Information - Templates

Name Description Version
Atmospheric extinction calibration
Site conditions (temperature, humidity) calibration
Optical source efficiency (muon emissivity) calibration
Reflectivity of mirrors calibration
Quantum efficiency of the detectors versus wavelength.
Detector amplification calibration
Electronic gain calibration for each amplification
Electronic threshold calibration
Dead time calibration
Pixel timing delay calibration
Telescope timing synchronisation delay calibration
Absolute timing calibration
Telescope mirrors alignment, structure deformation and stability calibration
Telescope field of view and uniformity calibration
Trigger system homogeneity across the field of view

Examples: HEGRA Templates

These data structures are already in use to process HEGRA data at ISDC
Name Description Version
HEGR-EVTS-ALL List of calibrated HEGRA events 1.0.4
HEGR-SKY.-IMA Contains the HEGRA sky image obtained from one or several runs 1.0.5
HEGR-SKY.-IMA-IDX Index of all HEGRA-IMAGE data structures in one FITS file 1.0.4
HEGR-EVTS-LCR Contains the HEGRA light-curve obtained from one or several runs 1.0.5
HEGR-EVTS-LCR-IDX Index of all HEGRA-LIGHTCURVE data structures in one FITS file 1.0