GSP
Quick Navigator

Search Site

Unix VPS
A - Starter
B - Basic
C - Preferred
D - Commercial
MPS - Dedicated
Previous VPSs
* Sign Up! *

Support
Contact Us
Online Help
Handbooks
Domain Status
Man Pages

FAQ
Virtual Servers
Pricing
Billing
Technical

Network
Facilities
Connectivity
Topology Map

Miscellaneous
Server Agreement
Year 2038
Credits
 

USA Flag

 

 

Man Pages
Astro::Coords::Elements(3) User Contributed Perl Documentation Astro::Coords::Elements(3)

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

  $c = new Astro::Coords::Elements( elements => \%elements );

This class is used by "Astro::Coords" for handling coordinates specified as orbital elements.

new
Instantiate a new object using the supplied options.

  $c = new Astro::Coords::Elements( elements => \%elements );
  $c = new Astro::Coords::Elements( elements => \@array );
    

Returns undef on error.

The elements can be specified either by using a reference to an array returned by the "array()" method of another elements object or in a reference to a hash containing the following keys:

suitable for the major planets:

 EPOCH           =  epoch of elements t0 (TT MJD)
 ORBINC          =  inclination i (radians)
 ANODE           =  longitude of the ascending node  [$\Omega$] (radians)
 PERIH           =  longitude of perihelion  [$\varpi$] (radians)
 AORQ            =  mean distance a (AU)
 E               =  eccentricity e
 AORL            =  mean longitude L (radians)
 DM              =  daily motion n (radians)
    

suitable for minor planets:

 EPOCH           =  epoch of elements t0 (TT MJD)
 ORBINC          =  inclination i (radians)
 ANODE           =  longitude of the ascending node  [$\Omega$] (radians)
 PERIH           =  argument of perihelion  [$\omega$] (radians)
 AORQ            =  mean distance a (AU)
 E               =  eccentricity e
 AORL            =  mean anomaly M (radians)
    

suitable for comets:

 EPOCH           =  epoch of elements t0 (TT MJD)
 ORBINC          =  inclination i (radians)
 ANODE           =  longitude of the ascending node  [$\Omega$] (radians)
 PERIH           =  argument of perihelion  [$\omega$] (radians)
 AORQ            =  perihelion distance q (AU)
 E               =  eccentricity e
 EPOCHPERIH      =  epoch of perihelion T (TT MJD)
    

See the documentation to palPlante() and palPertel() for more information. Keys must be upper case.

For comets if the only one epoch is specified it is assumed that the epochs are identical. This may cause problems if the epochs are not really close to each other.

In order to better match normal usage, EPOCH can also be specified as a string of the form 'YYYY mmm D.frac' (e.g. '1997 Apr 1.567'). (no decimal place after the month). This is the format used by JPL.

elements
Returns the hash containing the elements.

  %el = $c->elements;
    

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 "ELEMENTS".

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
Velocity definition. Always 'RADIO'.
vframe
Velocity reference frame. Always 'GEO'.
apply_offset
Overrided method to warn if "Astro::Coords::apply_offset" is called on this subclass.

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/

"Astro::PAL" is used for all internal astrometric calculations.

Tim Jenness <tjenness@cpan.org>

Copyright (C) 2001-2005 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 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

2022-04-08 perl v5.32.1

Search for    or go to Top of page |  Section 3 |  Main Index

Powered by GSP Visit the GSP FreeBSD Man Page Interface.
Output converted with ManDoc.