com.mhuss.AstroLib

Class Vsop

java.lang.Object

com.mhuss.AstroLib.Vsop

public class Vsop
extends java.lang.Object

This class wraps the VSOP87 data and provides VSOP planetary position calculation functions for Mercury through Neptune (VSOP doesn't handle the moon or Pluto).

Based on C code by Bill Gray (www.projectpluto.com)

Constructor Summary

Constructors

Constructor and Description
Vsop()

Method Summary

Modifier and Type	Method and Description
static void	calcAllLEs(LocationElements loc, double jcen, int planet) Calculate all three location elements of the specified planet at the given time.
static double	calcLE(double t, int planet, int ltype) Calculate a single location element (latitude, longitude, or radius).

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Vsop

public Vsop()

Method Detail

calcLE

public static double calcLE(double t,
                            int planet,
                            int ltype)

Calculate a single location element (latitude, longitude, or radius).

This function, using the simplified VSOP87 data in Meeus, can compute planetary positions in heliocentric ecliptic coordinates.

Longitude & latitude are in radians.

Parameters:

t - Time in Julian centuries from J2000

planet - One of the constants from Planets.MERCURY to Planets.NEPTUNE inclusive.

ltype - location element type:

• LocationElements.LONGITUDE for ecliptic longitude
• LocationElements.LATITUDE for ecliptic latitude
• LocationElements.RADIUS for distance from sun.

(These are ecliptic coordinates of date, by the way!)

Returns:

The selected element, or 0.0 if planet parameter is invalid.

calcAllLEs

public static void calcAllLEs(LocationElements loc,
                              double jcen,
                              int planet)

Calculate all three location elements of the specified planet at the given time.

Parameters:

loc - The LocationElements instance to populate

jcen - Time in Julian centuries from J2000

planet - The planet position to calculate, which must be in the range Planets.MERCURY to Planets.NEPTUNE inclusive.