NAME

Astro::FITS::HdrTrans::IRIS2 - IRIS-2 Header translations

SYNOPSIS

  %generic_headers = translate_from_FITS(\%FITS_headers, \@header_array);

  %FITS_headers = transate_to_FITS(\%generic_headers, \@header_array);

DESCRIPTION

Converts information contained in AAO IRIS2 FITS headers to and from generic headers. See Astro::FITS::HdrTrans for a list of generic headers.

METHODS

this_instrument

The name of the instrument required to match (case insensitively) against the INSTRUME/INSTRUMENT keyword to allow this class to translate the specified headers. Called by the default can_translate method.

  $inst = $class->this_instrument();

Returns "IRIS2".

COMPLEX CONVERSIONS

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)

to_AIRMASS_END

Converts FITS header value of zenith distance into airmass value.

from_AIRMASS_END

Converts airmass into zenith distance.

to_AIRMASS_START

Converts FITS header value of zenith distance into airmass value.

from_AIRMASS_START

Converts airmass into zenith distance.

to_COORDINATE_TYPE

Converts the EQUINOX FITS header into B1950 or J2000, depending on equinox value, and sets the COORDINATE_TYPE generic header.

to_DEC_SCALE

Calculate the Declination pixel scale from the CD matrix.

to_FILTER

Determine the filter name. Depends on the value of IR2_FILT.

to_GRATING_DISPERSION

Calculate grating dispersion.

Dispersion is only a function of grism and blocking filter used, but need to allow for various choices of blocking filter

to_GRATING_DISPERSION

Calculate grating wavelength.

Central wavelength is a function of grism + blocking filter + slit used. Assume offset slit used for H/Hs and Jl, otherwise centre slit is used. Central wavelengths computed for pixel 513, to match calculation used in ORAC-DR.

to_OBSERVATION_MODE

Determines the observation mode from the IR2_SLIT or IR2_GRSM FITS header values. If IR2_SLIT value is equal to "OPEN1", then the observation mode is imaging. Otherwise, the observation mode is spectroscopy. If IR2_GRSM is matches SAP or SIL then it is spectroscopy. IR2_GRSM is used in preference to IR2_SLIT.

to_RA_SCALE

Calculate the right-ascension pixel scale from the CD matrix.

to_UTDATE

Converts FITS header values into standard UT date value of the form YYYYMMDD.

from_UTDATE

Converts UT date in the form yyyymmdd to yyyy:mm:dd.

to_UTEND

Converts FITS header UT date/time values for the end of the observation into a Time::Piece object.

from_UTEND

Converts end date into two FITS headers for IRIS2: UTDATE (in the format YYYYMMDD) and UTEND (HH:MM:SS).

to_UTSTART

Converts FITS header UT date/time values for the start of the observation into a Time::Piece object.

from_UTSTART

Converts the date into two FITS headers for IRIS2: UTDATE (in the format YYYYMMDD) and UTSTART (HH:MM:SS).

to_X_BASE

Converts the decimal hours in the FITS header RABASE into decimal degrees for the generic header X_BASE.

from_X_BASE

Converts the decimal degrees in the generic header X_BASE into decimal hours for the FITS header RABASE.

to_X_SCALE

Converts a linear transformation matrix into a pixel scale in the right ascension axis. Results are in arcseconds per pixel.

to_Y_SCALE

Converts a linear transformation matrix into a pixel scale in the declination axis. Results are in arcseconds per pixel.

REVISION

 $Id$

SEE ALSO

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

AUTHOR

Brad Cavanagh <b.cavanagh@jach.hawaii.edu>, Tim Jenness <t.jenness@jach.hawaii.edu>

COPYRIGHT

Copyright (C) 2008 Science and Technology Facilities Council. Copyright (C) 2002-2007 Particle Physics and Astronomy Research Council. All Rights Reserved.

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