moonsun (version 0.1.3)

planet: Compute coordinates of a planet in solar system.

Description

This function computes equatorial coordinates for inner or outer planet for given Julian Day Number.

Usage

planet(jday = jd(), name = "", inner = FALSE, tp, ep, oo, e, a, i, om, th, mag)

Arguments

jday

Julian Day Number, default today

name

name of a planet (appended to dates in result)

inner

TRUE if it is inner, FALSE if outer planet

tp

period of a planet (tropical years)

ep

longitude at epoch 1990 January 0.00 (degrees)

oo

longitude of the perihelion (degrees)

e

eccentricity of the orbit

a

semi-major axis of the orbit (AU)

i

inclination of the orbit (degrees)

om

longitude of the ascending node (degrees)

th

angular diameter at 1 AU (arcsecs)

mag

visual magnitude at 1 AU

Value

An object of class eqc, containing position and other data for requested days, see planets() for details.

Details

The algorithm used here is fairly simple, it does not consider the Kepler equation, nor gravitational influences from other planets. See sun() for details.

This function is not called by user unless calculating a position for planetoid or modified data. The planets() function calls it with appropriate parameters automatically.

Examples

planets()