NAME
Astro::Catalog::Star - A generic star object in a stellar catalogue.
SYNOPSIS
$star = new Astro::Catalog::Star( ID => $id,
RA => $ra,
Dec => $dec,
Magnitudes => \%magnitudes,
MagErr => \%mag_errors,
Colours => \%colours,
ColErr => \%colour_errors,
Quality => $quality_flag,
Field => $field,
GSC => $in_gsc,
Distance => $distance_to_centre,
PosAngle => $position_angle,
X => $x_pixel_coord,
Y => $y_pixel_coord );DESCRIPTION
Stores generic meta-data about an individual stellar object from a catalogue.
If the catalogue has a field center the Distance and Position Angle properties should be used to store the direction to the field center, e.g. a star from the USNO-A2 catalogue retrieived from the ESO/ST-ECF Archive will have these properties.
REVISION
$Id: Star.pm,v 1.5 2002/01/24 22:15:09 aa Exp $
METHODS
Constructor
- new
-
Create a new instance from a hash of options
$star = new Astro::Catalog::Star( ID => $id, RA => $ra, Dec => $dec, Magnitudes => \%magnitudes, MagErr => \%mag_errors, Colours => \%colours, ColErr => \%colour_errors, Quality => $quality_flag, Field => $field, GSC => $in_gsc, Distance => $distance_to_centre, PosAngle => $position_angle, X => $x_pixel_coord, Y => $y_pixel_coord );returns a reference to an Astro::Catalog::Star object.
Accessor Methods
- id
-
Return (or set) the ID of the star
$id = $star->id(); $star->id( $id ); - RA
-
Return (or set) the current object R.A.
$ra = $star->ra(); $star->ra( $ra ); - Dec
-
Return (or set) the current target Declination defined for the DSS query
$dec = $dss->dec(); $dss->dec( $dec );where $dec should be a string of the form "+-HH MM SS.SS", e.g. +43 35 09.5 or -40 25 67.89
- Magnitudes
-
Set the UBVRIHK magnitudes of the object, takes a reference to a hash of magnitude values
my %mags = ( B => '16.5', V => '15.4', R => '14.3' ); $star->magnitudes( \%mags );additional calls to magnitudes() will append, not replace, additional magnitude values, magnitudes for filters already existing will be over-written.
- MagErr
-
Set the error in UBVRIHK magnitudes of the object, takes a reference to a hash of error values
my %mag_errors = ( B => '0.3', V => '0.1', R => '0.4' ); $star->magerr( \%mag_errors );additional calls to magerr() will append, not replace, additional error values, errors for filters already existing will be over-written.
- Colours
-
Set the colour values for the object, takes a reference to a hash of colours
my %cols = ( 'B-V' => '0.5', 'B-R' => '0.4' ); $star->colours( \%cols );additional calls to colours() will append, not replace, colour values, altough for colours which already have defined values, these values will be over-written.
- ColErr
-
Set the colour error values for the object, takes a reference to a hash of colour errors
my %col_errors = ( 'B-V' => '0.02', 'B-R' => '0.05' ); $star->colerr( \%col_errors );additional calls to colerr() will append, not replace, colour error values, altough for errors which already have defined values, these values will be over-written.
- what_filters
-
Returns a list of the filters for which the object has defined values.
@filters = $star->what_filters(); $num = $star->what_filters();if called in a scalar context it will return the number of filters which have defined magnitudes in the object.
- what_colours
-
Returns a list of the colours for which the object has defined values.
@colours = $star->what_colours(); $num = $star->what_colours();if called in a scalar context it will return the number of colours which have defined values in the object.
- get_magnitude
-
Returns the magnitude for the supplied filter if available
$magnitude = $star->get_magnitude( 'B' ); - get_errors
-
Returns the error in the magnitude value for the supplied filter if available
$mag_errors = $star->get_errors( 'B' ); - get_colour
-
Returns the value of the supplied colour if available
$colour = $star->get_colour( 'B-V' ); - get_colourerror
-
Returns the error in the colour value for the supplied colour if available
$col_errors = $star->get_colourerr( 'B-V' ); - quality
-
Return (or set) the quality flag of the star
$quality = $star->quailty(); $star->quality( 0 );for example for the USNO-A2 catalogue, 0 denotes good quality, and 1 denotes a possible problem object. In the generic case any flag value, including a boolean, could be used.
- field
-
Return (or set) the field parameter for the star
$field = $star->field(); $star->field( '0080' ); - gsc
-
Return (or set) the GSC flag for the object
$gsc = $star->gsc(); $star->gsc( 'TRUE' );the flag is TRUE if the object is known to be in the Guide Star Catalogue, and FALSE otherwise.
- distance
-
Return (or set) the distance from the field centre
$distance = $star->distance(); $star->distance( '0.009' );e.g. for the USNO-A2 catalogue.
- posangle
-
Return (or set) the position angle from the field centre
$position_angle = $star->posangle(); $star->posangle( '50.761' );e.g. for the USNO-A2 catalogue.
- x
-
Return (or set) the X pixel co-ordinate of the star
$x = $star->x(); $star->id( $x ); - y
-
Return (or set) the Y pixel co-ordinate of the star
$y = $star->y(); $star->id( $y );
General Methods
- configure
-
Configures the object from multiple pieces of information.
$star->configure( %options );Takes a hash as argument with the list of keywords.
COPYRIGHT
Copyright (C) 2001 University of Exeter. All Rights Reserved.
This program was written as part of the eSTAR project and is free software; you can redistribute it and/or modify it under the terms of the GNU Public License.
AUTHORS
Alasdair Allan <aa@astro.ex.ac.uk>,