NAME

Astro::Telescope - class for obtaining telescope information

SYNOPSIS

use Astro::Telescope;

$tel = new Astro::Telescope( 'UKIRT' );

$latitude = $tel->lat;
$longitude = $tel->long;
$altitude = $tel->alt;

%limits = $tel->limits;

@telescopes = Astro::Telescope->telNames();

DESCRIPTION

A class for handling properties of individual telescopes such as longitude, latitude, height and observational limits.

METHODS

Constructor

new

Create a new telescope object. Takes the telescope abbreviation as the single argument.

$tel = new Astro::Telescope( 'VLA' );

An argument must be supplied. Returns undef if the telescope is not recognized.

Acessor Methods

name

Returns the abbreviated name of the telescope. This is the same as that given to the constructor (although it will be upper-cased).

The object can be reconfigured to a new telescope by supplying a new abbreviation to this method.

$tel->name('JCMT');

The object will not change state if the name is not known.

fullname

Returns the full name of the telescope. For example, if the abbreviated name is "JCMT" this will return "JCMT 15 metre".

long

Longitude of the telescope (east +ve). By default this is in radians.

An argument of "d" or "s" can be supplied to retrieve the value in decimal degrees or sexagesimal string format respectively.

$string = $tel->long("s");

lat

Geodetic latitude of the telescope. By default this is in radians.

An argument of "d" or "s" can be supplied to retrieve the value in decimal degrees or sexagesimal string format respectively.

$deg = $tel->lat("d");

alt

Altitude of the telescope in metres.

limits

Return the telescope limits.

%limits = $tel->limits;

The limits are returned as a hash with the following keys:

type

Specifies the way in which the limits are specified. Effectively the telescope mount. Values of "AZEL" (for altaz telescopes) and "HADEC" (for equatorial telescopes) are currently supported.

el

Elevation limit of the telescope. Value is a hash with keys max and min. Units are in radians. Only used if type is AZEL.

ha

Hour angle limit of the telescope. Value is a hash with keys max and min. Units are in radians. Only used if type is HADEC.

dec

Declination limit of the telescope. Value is a hash with keys max and min. Units are in radians. Only used if type is HADEC.

Only some telescopes have limits defined (please send patches with new limits if you know them). If limits are not available for this telescope an empty list is returned.

Class Methods

telNames

Obtain a sorted list of all supported telescope names.

@names = Astro::Telescope->telNames;

REQUIREMENTS

The list of telescope properties is currently obtained from those provided by SLALIB (Astro::SLA).

AUTHOR

Tim Jenness <t.jenness@jach.hawaii.edu>

COPYRIGHT

Copyright (C) 1998-2002 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.