
Astro::FITS::HdrTrans::JAC - Base class for translation of Joint Astronomy Centre instruments.

use Astro::FITS::HdrTrans::JAC;

This class provides a generic set of translations that are common to instrumentation from the Joint Astronomy Centre. It should not be used directly for translation of instrument FITS headers.
This routine overrides the base class implementation to enable the caches to be cleared and for the location of the DATE-OBS/DATE-END field to be found so that base class implementations will work correctly.
This means that some conversion methods (in particular those using time in a base class) may not work properly outside the context of a full translation unless they have been subclassed locally.

These methods are more complicated than a simple mapping. We have to provide both from- and to-FITS conversions All these routines are methods and the to_ routines all take a reference to a hash and return the translated value (a many-to-one mapping). The from_ methods take a reference to a generic hash and return a translated hash (sometimes these are many-to-many).
Converts the OBSID header directly into the OBSERVATION_ID generic header, or if that header does not exist, converts the INSTRUME, RUNNR, and DATE-OBS headers into OBSERVATION_ID.
The form of the observation ID string is documented in JSA/ANA/001 (http://docs.jach.hawaii.edu/JCMT/JSA/ANA/001/jsa_ana_001.pdf).
Sort out DATE-OBS and DATE-END in cases where they are not available directly. This is mainly an issue with database retrievals where the date format is not FITS compliant.
Astro::FITS::HdrTrans::JAC->_fix_dates( \%headers );

$Id$

Astro::FITS::HdrTrans, Astro::FITS::HdrTrans::Base.

Brad Cavanagh <b.cavanagh@jach.hawaii.edu>.

Copyright (C) 2007 Science and Technology Facilities Council. Copyright (C) 2006 Particle Physics and Astronomy Research Council. All Rights Reserved.
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