NAME

Astro::FITS::HdrTrans::INGRID - WHT INGRID translations

SYNOPSIS

  use Astro::FITS::HdrTrans::INGRID;

  %gen = Astro::FITS::HdrTrans::INGRID->translate_from_FITS( %hdr );

DESCRIPTION

This class provides a generic set of translations that are specific to the INGRID camera of the William Herschel Telescope.

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 "INGRID".

COMPLEX CONVERSIONS

to_DEC_BASE

Converts the base declination from sexagesimal d:m:s to decimal degrees using the CAT-DEC keyword, defaulting to 0.0.

to_DEC_SCALE

Sets the declination scale in arcseconds per pixel. The CCDYPIXE and INGPSCAL headers are used when both are defined. Otherwise it returns a default value of 0.2387 arcsec/pixel, assuming north is up.

to_DEC_TELESCOPE_OFFSET

Sets the declination telescope offset in arcseconds. It uses the CAT-DEC and DEC keywords to derive the offset, and if either does not exist, it returns a default of 0.0.

to_DETECTOR_READ_TYPE

Returns the UKIRT-like detector type "STARE" or "NDSTARE" from the FITS REDMODE and NUMREADS keywords.

This is guesswork at present.

to_DR_RECIPE

Returns the data-reduction recipe name. The selection depends on the values of the OBJECT and OBSTYPE keywords. The default is "QUICK_LOOK". A dark returns "REDUCE_DARK", and an object's recipe is "JITTER_SELF_FLAT".

to_EQUINOX

Returns the equinox in decimal years. It's taken from the CAT-EQUI keyword, if it exists, defaulting to 2000.0 otherwise.

to_GAIN

Returns the gain in electrons per data number. This is taken from the GAIN keyword, with a default of 4.1.

to_NUMBER_OF_OFFSETS

Returns the number of offsets. It uses the UKIRT convention so it is equivalent to the number of dither positions plus one. The value is derived from the OBJECT keyword, with a default of 6.

to_OBJECT

Reeturns the object name. It is extracted from the OBJECT keyword.

to_OBSERVATION_TYPE

Determines the observation type from the OBSTYPE keyword provided it is "TARGET" for an object dark frame.

to_RA_BASE

Converts the base right ascension from sexagesimal h:m:s to decimal degrees using the CAT-RA keyword, defaulting to 0.0.

to_RA_SCALE

Sets the right-ascension scale in arcseconds per pixel. The CCDXPIXE and INGPSCAL headers are used when both are defined. Otherwise it returns a default value of 0.2387 arcsec/pixel, assuming east is to the left.

to_RA_TELESCOPE_OFFSET

Sets the right-ascension telescope offset in arcseconds. It uses the CAT-RA, RA, CAT-DEC keywords to derive the offset, and if any of these keywords does not exist, it returns a default of 0.0.

to_ROTATION

Returns the orientation of the detector in degrees anticlockwise from north via east.

to_SPEED_GAIN

Returns the speed gain. This is either "Normal" or "HiGain", the selection depending on the value of the CCDSPEED keyword.

to_STANDARD

Returns whether or not the observation is of a standard source. It is deemed to be a standard when the OBSTYPE keyword is "STANDARD".

to_UTDATE

Returns the UT date as Time::Piece object. It copes with non-standard format in DATE-OBS.

to_UTEND

Returns the UT time of the end of the observation as a Time::Piece object.

to_UTSTART

Returns an estimated UT time of the start of the observation as a Time::Piece object. The start time is derived from the DATE-OBS keyword and if DATE-OBS only supplies a date, the time from the UTSTART keyword is appended before conversaion to a Time::Piece object.

to_X_LOWER_BOUND

Returns the lower bound along the X-axis of the area of the detector as a pixel index.

to_X_REFERENCE_PIXEL

Specifies the X-axis reference pixel near the frame centre. It uses the nominal reference pixel if that is correctly supplied, failing that it takes the average of the bounds, and if these headers are also absent, it uses a default which assumes the full array.

to_X_UPPER_BOUND

Returns the upper bound along the X-axis of the area of the detector as a pixel index.

to_Y_LOWER_BOUND

Returns the lower bound along the Y-axis of the area of the detector as a pixel index.

to_Y_REFERENCE_PIXEL

Specifies the Y-axis reference pixel near the frame centre. It uses the nominal reference pixel if that is correctly supplied, failing that it takes the average of the bounds, and if these headers are also absent, it uses a default which assumes the full array.

to_Y_UPPER_BOUND

Returns the upper bound along the Y-axis of the area of the detector as a pixel index.

# Supplementary methods for the translations # ------------------------------------------

HELPER ROUTINES

These are INGRID-specific helper routines.

dms_to_degrees

Converts a sky angle specified in d:m:s format into decimal degrees. The argument is the sexagesimal-format angle.

get_UT_date

Returns the UT date in YYYYMMDD format. It parses the non-standard ddMmmyy DATE-OBS keyword.

hms_to_degrees

Converts a sky angle specified in h:m:s format into decimal degrees. It takes no account of latitude. The argument is the sexagesimal format angle.

rotation

Derives the rotation angle in degrees from the ROTSKYPA keyword, with a default of 0.0.

REVISION

 $Id: INGRID.pm 14879 2008-02-13 21:51:31Z timj $

SEE ALSO

Astro::FITS::HdrTrans, Astro::FITS::HdrTrans::UKIRT.

AUTHOR

Malcolm J. Currie <mjc@star.rl.ac.uk> 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) 2003-2005 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.