The preliminary version of documentation of the format for the interchange of calibrated optical/IR data being developed by Tom Pauls of NRL and John Young of COAST was presented and a number of issues discussed.
The proposed format is in the general form of a relational database with different components stored in FITS binary tables. The different components are related by means of indices into other tables. For example the target being observed is given as an index in the target table.
The discussion points were the following:
These were discussed jointly. It was generally concluded that there should be a separate table type for each data type. There was no general sentiment in favor of additional types at present but it will be straightforward to implement new data types as new table types. It was also concluded that the names of the tables needed to be explicitly for Optical/IR interferometry data. The new names are the following:
|OI_ARRAY||specifies array geometry|
|OI_TARGET||specifies targets, positions etc.|
|OI_WAVELENGTH||gives the effective wavelengths of the spectral channels|
|OI_VIS||gives complex visibilities|
|OI_VIS2||gives visibility squared|
|OI_T3||gives triple product amplitudes and phases|
It was concluded that there was no strong argument for using virtual keywords and the simplicity of not using them more than made up for possible increases in storage space.
The discussion of this issue was inconclusive.
There was a general consensus that physical units as well as normalized units should be allowed by the format definition.
Preben Grosbol (ESO) expressed concern that the relational database aspect of the format might be disrupted if constituent tables were moved to separate files. A possible solution is to include a unique identifier in each data set to establish which sets of tables go together.
Data Exchange Standard | OLBIN