ELEM2XYZ

Name

elem2xyz

Purpose (one Line Only)

Compute position given orbital elements (2-body Keplerian)

Description

Calling Sequence

elem2xyz,jdepoch,manom,arg,node,inc,ecc,semi,jdpos,x,y,z

Inputs

jdepoch - Julian date of mean anomaly
m - Mean anomaly (radians)
arg - Argument of perihelion (radians)
node - Longitude of ascending node (radians)
inc - Inclination (radians)
ecc - Eccentricity
a - Semi-major axis (AU)
jdpos - Julian date desired (scalar or vector)

Optional Input Parameters

Keyword Input Parameters

ECLIPTIC - Flag, if set returns x,y,z in Heliocentric ecliptic coordinates

Outputs

x - Heliocentric x coordinates (AU)
y - Heliocentric y coordinates (AU)
z - Heliocentric z coordinates (AU)

Keyword Output Parameters

Common Blocks

Side Effects

Restrictions

Procedure

Note that there is nothing special about the time. You can, if you wish
specify jdepoch as 0. and then have jdpos be a simple incrementing
vector starting at zero. In other words, jdpos is really just relative
to jdepoch.

Modification History

2002/05/29 - Marc W. Buie, Lowell Observatory. Ported from fortran routines
supplied by Larry Wasserman and Ted Bowell.
2012/12/09, MWB, changed calling sequence to require time and now allow
vector input on jdpos.
2013/08/16, MWB, improve options for mixing and matching vector and
scalar inputs.
2014/01/09, MWB, minor tweak to keep the propagated epoch during
the calculation, can speed it up in certain cases.