Main.java Source code

Introduction

Here is the source code for Main.java

Source

//package com.java2s;

public class Main {
    /**
     * Calculate the apparent longitude of the sun.
     *
     * @param  t number of Julian centuries since J2000.
     * @return Sun's apparent longitude in degrees.
     */
    private static double sunApparentLongitude(final double t) {
        final double omega = Math.toRadians(125.04 - 1934.136 * t);
        return sunTrueLongitude(t) - 0.00569 - 0.00478 * Math.sin(omega);
    }

    /**
     * Calculate the true longitude of the sun. This the geometric mean
     * longitude plus a correction factor ("equation of center" for the
     * sun).
     *
     * @param  t number of Julian centuries since J2000.
     * @return Sun's true longitude in degrees.
     */
    private static double sunTrueLongitude(final double t) {
        return sunGeometricMeanLongitude(t) + sunEquationOfCenter(t);
    }

    /**
     * Calculate the Geometric Mean Longitude of the Sun.
     * This value is close to 0 degree at the spring equinox,
     * 90 degree at the summer solstice, 180 degree at the automne equinox
     * and 270 degree at the winter solstice.
     *
     * @param  t number of Julian centuries since J2000.
     * @return Geometric Mean Longitude of the Sun in degrees,
     *         in the range 0 degree (inclusive) to 360 degree (exclusive).
     */
    private static double sunGeometricMeanLongitude(final double t) {
        double L0 = 280.46646 + t * (36000.76983 + 0.0003032 * t);
        L0 = L0 - 360 * Math.floor(L0 / 360);
        return L0;
    }

    /**
     * Calculate the equation of center for the sun. This value is a correction
     * to add to the geometric mean longitude in order to get the "true" longitude
     * of the sun.
     *
     * @param  t number of Julian centuries since J2000.
     * @return Equation of center in degrees.
     */
    private static double sunEquationOfCenter(final double t) {
        final double m = Math.toRadians(sunGeometricMeanAnomaly(t));
        return Math.sin(1 * m) * (1.914602 - t * (0.004817 + 0.000014 * t))
                + Math.sin(2 * m) * (0.019993 - t * (0.000101)) + Math.sin(3 * m) * (0.000289);
    }

    /**
     * Calculate the Geometric Mean Anomaly of the Sun.
     *
     * @param  t number of Julian centuries since J2000.
     * @return Geometric Mean Anomaly of the Sun in degrees.
     */
    private static double sunGeometricMeanAnomaly(final double t) {
        return 357.52911 + t * (35999.05029 - 0.0001537 * t);
    }
}