Astro::Catalog::Star - A generic star object in a stellar catalogue.

COPYRIGHT
AUTHORS

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 1.6 2002/03/29 17:40:17 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_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' );

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.

freeze

Method to return a blessed reference to the object so that we can store ths object on disk using Data::Dumper module.

COPYRIGHT

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>,

Astro::Catalog::Star - A generic star object in a stellar catalogue.