Tim Jenness > Astro-Coords-0.12 > Astro::Coords::Elements
Module Version: 0.04   Source   Latest Release: Astro-Coords-0.18

# NAME

Astro::Coords::Elements - Specify astronomical coordinates using orbital elements

# General Methods

array

Return back 11 element array with first element containing the string "ELEMENTS", the next two elements as undef and up to 8 following elements containing the orbital elements in the order presented in the documentation of the constructor.

This method returns a standardised set of elements across all types of coordinates.

Note that for JFORM=3 (Comet) case the epoch of perihelion is stored as the 8th element (the epoch of the elements is still returned as the first element) [corresponding to array index 10]. This usage of the final element can be determined by noting that the element before it (AORL) will be undefined in the case of JFORM=3. If AORL is defined then the Epoch of perihelion will not be written even if it is defined.

type

Returns the generic type associated with the coordinate system. For this class the answer is always "RADEC".

This is used to aid construction of summary tables when using mixed coordinates.

It could be done using isa relationships.

stringify

Stringify overload. Returns comma-separated list of the elements.

summary

Return a one line summary of the coordinates. In the future will accept arguments to control output.

  $summary =$c->summary();
apparent

Return the apparent RA and Dec (as two Astro::Coords::Angle objects) for the current coordinates and time. Includes perterbation corrections to convert the elements to the required epoch.

Returns empty list on error.

rv

Radial velocity of the planet relative to the Earth geocentre.

vdefn

vframe

Velocity reference frame. Always 'GEO'.

# NOTES

Usually called via Astro::Coords.

Useful sources of orbital elements can be found at http://ssd.jpl.nasa.gov and http://cfa-www.harvard.edu/iau/Ephemerides/

# REQUIREMENTS

Astro::SLA is used for all internal astrometric calculations.

# AUTHOR

Tim Jenness <tjenness@cpan.org>

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 3 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

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