Astro::FITS::HdrTrans module ---------------------------- What is it? ----------- Astro::FITS::HdrTrans and associated sub-classes are tools for translating instrument-specific FITS headers into generically named headers. Requirements ------------ The Astro::FITS::HdrTrans module has minimal requirements on other modules; only Carp and Time::Piece are required. Instrument-specific sub-classes of Astro::FITS::HdrTrans may require other modules to be installed, depending on the transformations those sub-classes make. As an example, the translation sub-class for IRIS2 (an imaging spectrometer used at the Anglo-Australian Telescope) requires Math::Trig in order to do zenith distance to airmass translations. Adding Subclasses ----------------- Adding subclasses to do translations for other instruments should be fairly straight-forward. The first step is writing an appropriate valid_class function that returns true or false depending on the contents of the header passed to it. You must come up with a unique way of figuring out if the header is one that your subclass will translate; using the instrument name should usually be enough. After you have done that it comes time to write the actual translations. One-to-one translations are handled in the %hdr hash, with the generic headers being the keys and the instrument-specific headers being the values. For many-to-one translations, set up the to_ and from_ methods. UTDATE, UTSTART, and UTEND be returned as Time::Piece objects when translating to generic headers, and must be passed as Time::Piece objects when translating to instrument-specific headers. Keep this in mind when writing translations for these three. Examples of translations can be found in the Astro::FITS::HdrTrans::IRCAM subclass. Don't forget to return a true value from your subclass by putting "1;" on the last line! Where can I get it? ------------------- The package is available from CPAN . Installation ------------ Installation is automated using the ExtUtils::MakeMaker library % perl Makefile.PL % make % make test % make install Authors ------- The module was written by Brad Cavanagh of the Joint Astronomy Centre (JAC) in Hawaii. Maintainer ---------- The package is currently maintained by Brad Cavanagh . License ------- This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful,but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 59 Temple Place,Suite 330, Boston, MA 02111-1307, USA