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FITS extensions

A FITS file is composed by one or several Header Data Units (HDU) or extensions. An extension can be an image or a table. For the purpose of HFA we are defining some standard extensions:
HFA Standard extensions
NameTypeDescription
WCALIB_RELATIONBinary tableWavelength calibration relation, this extension is mandatory in the reference arcs.
WCALIB_LINCATBinary tableCatalogue of spectral lines used for the wavelength calibration, this extension is mandatory in the reference arcs.

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