NAME

Astro::FITS::HdrTrans::JCMT_GSD_DB - JCMT GSD Database header translations

DESCRIPTION

Converts information contained in JCMT heterodyne database headers to and from generic headers. See Astro::FITS::HdrTrans for a list of generic headers.

METHODS

can_translate

Returns true if the supplied headers can be handled by this class.

$cando = $class->can_translate( \%hdrs );

For this class, the method will return true if the "GSDFILE" header exists and the "SCA#" header exist.

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_INSTRUMENT

Sets the INSTRUMENT generic header. For RxA3i, sets the value to RXA3. For RxB, sets the value to RXB3.

to_OBSERVATION_ID

Calculate a unique Observation ID.

to_UTDATE

Translates the DATE_OBS or LONGDATEOBS header into a YYYYMMDD integer.

to_UTSTART

Translates the DB date header into a Time::Piece object.

to_UTEND

Translates the database date header into a Time::Piece object and adds on the exposure time.

to_BANDWIDTH_MODE

Uses the NORSECT (number of backend sections), NOFCHAN (number of frontend output channels) and NOBCHAN (number of channels) to form a string that is of the format 250MHzx2048. To obtain this, the bandwidth (250MHz in this example) is calculated as 125MHz * NORSECT / NOFCHAN. The number of channels is taken directly and not manipulated in any way.

If appropriate, the bandwidth may be given in GHz.

to_EXPOSURE_TIME

to_SYSTEM_VELOCITY

Translate the VREF and C12VDEF headers into one combined header.

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) 2003-2007 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