NAME
Astro::FITS::HdrTrans::IRCAM - Translate FITS headers into generic headers and back again
DESCRIPTION
Describes conversions between generic headers and those for the United Kingdom Infrared Telescope IRCAM infrared camera.
REVISION
$Id: IRCAM.pm,v 1.14 2003/09/16 02:20:03 bradc Exp $
METHODS
These methods provide an interface to the class, allowing the base class to determine if this class is the appropriate one to use for the given headers.
- valid_class
-
$valid = valid_class( \%headers );
This method takes one argument: a reference to a hash containing the untranslated headers.
This method returns true (1) or false (0) depending on if the headers can be translated by this method.
For this class, the method will return true if the INSTRUME header exists, and its value matches the regular expression
/^ircam/i
, or if theINSTRUMENT
header exists and its value matches the regular expression/^ircam$/i
.
TRANSLATION METHODS
These methods provide many-to-one mappings between FITS headers and generic headers. An example of a method defined in this section would be one that converts UT date and UT hour FITS headers into one combined UT datetime generic header. These mappings can also use calculations, for example converting a zenith distance to airmass.
These methods are named backwards from the translate_from_FITS
and translate_to_FITS
methods in that we are translating to and from generic headers. As an example, a method to convert to a generic airmass header would be named to_AIRMASS
.
The format of these methods is to_HEADER
and from_HEADER
. to_
methods accept a hash reference as an argument and return a scalar value (typically a string). from_
methods accept a hash reference as an argument and return a hash.
- to_INST_DHS
-
Sets the INST_DHS header.
- to_COORDINATE_TYPE
-
Converts the
EQUINOX
FITS header into B1950 or J2000, depending on equinox value, and sets theCOORDINATE_TYPE
generic header. - to_COORDINATE_UNITS
-
Sets the
COORDINATE_UNITS
generic header to "degrees". - to_POLARIMETRY
- to_UTDATE
-
Converts FITS header values into
Time::Piece
object. - from_UTDATE
-
Converts UT date in
Time::Piece
object intoYYYYMMDD
format for IDATE header. - to_UTSTART
-
Converts FITS header UT date/time values for the start of the observation into a
Time::Piece
object. - from_UTSTART
-
Converts a
Time::Piece
object into two FITS headers for IRCAM: IDATE (in the format YYYYMMDD) and RUTSTART (decimal hours). - to_UTEND
-
Converts FITS header UT date/time values for the end of the observation into a
Time::Piece
object. - from_UTEND
-
Converts a
Time::Piece
object into two FITS headers for IRCAM: IDATE (in the format YYYYMMDD) and RUTEND (decimal hours). - to_RA_BASE
-
Converts the decimal hours in the FITS header
RABASE
into decimal degrees for the generic headerRA_BASE
. - from_RA_BASE
-
Converts the decimal degrees in the generic header
RA_BASE
into decimal hours for the FITS headerRABASE
.
VARIABLES
- %hdr
-
Contains one-to-one mappings between FITS headers and generic headers. Keys are generic headers, values are FITS headers.
AUTHOR
Brad Cavanagh <b.cavanagh@jach.hawaii.edu>
COPYRIGHT
Copyright (C) 2003 Particle Physics and Astronomy Research Council. All Rights Reserved.
This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.