Java tutorial
/** * Copyright (c) 2010-2015, openHAB.org and others. * * All rights reserved. This program and the accompanying materials * are made available under the terms of the Eclipse Public License v1.0 * which accompanies this distribution, and is available at * http://www.eclipse.org/legal/epl-v10.html */ package org.openhab.binding.astro.internal.calc; import java.util.Calendar; import org.apache.commons.lang.time.DateUtils; import org.openhab.binding.astro.internal.model.Position; import org.openhab.binding.astro.internal.model.Range; import org.openhab.binding.astro.internal.model.Sun; import org.openhab.binding.astro.internal.model.SunEclipse; import org.openhab.binding.astro.internal.util.DateTimeUtils; /** * Calculates the SunPosition (azimuth, elevation) and Sun data. * * @author Gerhard Riegler * @since 1.6.0 * @see based on the calculations of http://www.suncalc.net */ public class SunCalc { private static final double J2000 = 2451545.0; public static final double DEG2RAD = Math.PI / 180; public static final double RAD2DEG = 180. / Math.PI; private static final double M0 = 357.5291 * DEG2RAD; private static final double M1 = 0.98560028 * DEG2RAD; private static final double J0 = 0.0009; private static final double J1 = 0.0053; private static final double J2 = -0.0069; private static final double C1 = 1.9148 * DEG2RAD; private static final double C2 = 0.0200 * DEG2RAD; private static final double C3 = 0.0003 * DEG2RAD; private static final double P = 102.9372 * DEG2RAD; private static final double E = 23.45 * DEG2RAD; private static final double TH0 = 280.1600 * DEG2RAD; private static final double TH1 = 360.9856235 * DEG2RAD; private static final double SUN_ANGLE = -0.83; private static final double SUN_DIAMETER = 0.53 * DEG2RAD; // sun diameter private static final double H0 = SUN_ANGLE * DEG2RAD; private static final double H1 = -6.0 * DEG2RAD; // nautical twilight angle private static final double H2 = -12.0 * DEG2RAD; // astronomical twilight // angle private static final double H3 = -18.0 * DEG2RAD; // darkness angle private static final double MINUTES_PER_DAY = 60 * 24; private static final int CURVE_TIME_INTERVAL = 20; // 20 minutes private static final double JD_ONE_MINUTE_FRACTION = 1.0 / 60 / 24; /** * Calculates the sun position (azimuth and elevation). */ public void setSunPosition(Calendar calendar, double latitude, double longitude, Sun sun) { double lw = -longitude * DEG2RAD; double phi = latitude * DEG2RAD; double j = DateTimeUtils.dateToJulianDate(calendar); double m = getSolarMeanAnomaly(j); double c = getEquationOfCenter(m); double lsun = getEclipticLongitude(m, c); double d = getSunDeclination(lsun); double a = getRightAscension(lsun); double th = getSiderealTime(j, lw); double azimuth = getAzimuth(th, a, phi, d) / DEG2RAD; double elevation = getElevation(th, a, phi, d) / DEG2RAD; Position position = sun.getPosition(); position.setAzimuth(azimuth + 180); position.setElevation(elevation); } /** * Returns true, if the sun is up all day (no rise and set). */ private boolean isSunUpAllDay(Calendar calendar, double latitude, double longitude) { Calendar cal = DateTimeUtils.truncateToMidnight(calendar); Sun sun = new Sun(); for (int minutes = 0; minutes <= MINUTES_PER_DAY; minutes += CURVE_TIME_INTERVAL) { setSunPosition(cal, latitude, longitude, sun); if (sun.getPosition().getElevation() < SUN_ANGLE) { return false; } cal.add(Calendar.MINUTE, CURVE_TIME_INTERVAL); } return true; } /** * Calculates all sun rise and sets at the specified coordinates. */ public Sun getSunInfo(Calendar calendar, double latitude, double longitude) { return getSunInfo(calendar, latitude, longitude, false); } private Sun getSunInfo(Calendar calendar, double latitude, double longitude, boolean onlyAstro) { double lw = -longitude * DEG2RAD; double phi = latitude * DEG2RAD; double j = DateTimeUtils.midnightDateToJulianDate(calendar) + 0.5; double n = getJulianCycle(j, lw); double js = getApproxSolarTransit(0, lw, n); double m = getSolarMeanAnomaly(js); double c = getEquationOfCenter(m); double lsun = getEclipticLongitude(m, c); double d = getSunDeclination(lsun); double jtransit = getSolarTransit(js, m, lsun); double w0 = getHourAngle(H0, phi, d); double w1 = getHourAngle(H0 + SUN_DIAMETER, phi, d); double jset = getSunsetJulianDate(w0, m, lsun, lw, n); double jsetstart = getSunsetJulianDate(w1, m, lsun, lw, n); double jrise = getSunriseJulianDate(jtransit, jset); double jriseend = getSunriseJulianDate(jtransit, jsetstart); double w2 = getHourAngle(H1, phi, d); double jnau = getSunsetJulianDate(w2, m, lsun, lw, n); double Jciv2 = getSunriseJulianDate(jtransit, jnau); double w3 = getHourAngle(H2, phi, d); double w4 = getHourAngle(H3, phi, d); double jastro = getSunsetJulianDate(w3, m, lsun, lw, n); double jdark = getSunsetJulianDate(w4, m, lsun, lw, n); double jnau2 = getSunriseJulianDate(jtransit, jastro); double jastro2 = getSunriseJulianDate(jtransit, jdark); Sun sun = new Sun(); sun.setAstroDawn(new Range(DateTimeUtils.toCalendar(jastro2), DateTimeUtils.toCalendar(jnau2))); sun.setAstroDusk(new Range(DateTimeUtils.toCalendar(jastro), DateTimeUtils.toCalendar(jdark))); if (onlyAstro) { return sun; } sun.setNoon(new Range(DateTimeUtils.toCalendar(jtransit), DateTimeUtils.toCalendar(jtransit + JD_ONE_MINUTE_FRACTION))); sun.setRise(new Range(DateTimeUtils.toCalendar(jrise), DateTimeUtils.toCalendar(jriseend))); sun.setSet(new Range(DateTimeUtils.toCalendar(jsetstart), DateTimeUtils.toCalendar(jset))); sun.setCivilDawn(new Range(DateTimeUtils.toCalendar(Jciv2), DateTimeUtils.toCalendar(jrise))); sun.setCivilDusk(new Range(DateTimeUtils.toCalendar(jset), DateTimeUtils.toCalendar(jnau))); sun.setNauticDawn(new Range(DateTimeUtils.toCalendar(jnau2), DateTimeUtils.toCalendar(Jciv2))); sun.setNauticDusk(new Range(DateTimeUtils.toCalendar(jnau), DateTimeUtils.toCalendar(jastro))); boolean isSunUpAllDay = isSunUpAllDay(calendar, latitude, longitude); // daylight Range daylightRange = new Range(); if (sun.getRise().getStart() == null && sun.getRise().getEnd() == null) { if (isSunUpAllDay) { daylightRange = new Range(DateTimeUtils.truncateToMidnight(calendar), DateTimeUtils.truncateToMidnight(addDays(calendar, 1))); } } else { daylightRange = new Range(sun.getRise().getEnd(), sun.getSet().getStart()); } sun.setDaylight(daylightRange); // morning night Sun sunYesterday = getSunInfo(addDays(calendar, -1), latitude, longitude, true); Range morningNightRange = null; if (sunYesterday.getAstroDusk().getEnd() != null && DateUtils.isSameDay(sunYesterday.getAstroDusk().getEnd(), calendar)) { morningNightRange = new Range(sunYesterday.getAstroDusk().getEnd(), sun.getAstroDawn().getStart()); } else if (isSunUpAllDay) { morningNightRange = new Range(); } else { morningNightRange = new Range(DateTimeUtils.truncateToMidnight(calendar), sun.getAstroDawn().getStart()); } sun.setMorningNight(morningNightRange); // evening night Range eveningNightRange = null; if (sun.getAstroDusk().getEnd() != null && DateUtils.isSameDay(sun.getAstroDusk().getEnd(), calendar)) { eveningNightRange = new Range(sun.getAstroDusk().getEnd(), DateTimeUtils.truncateToMidnight(addDays(calendar, 1))); } else { eveningNightRange = new Range(); } sun.setEveningNight(eveningNightRange); // night if (isSunUpAllDay) { sun.setNight(new Range()); } else { Sun sunTomorrow = getSunInfo(addDays(calendar, 1), latitude, longitude, true); sun.setNight(new Range(sun.getAstroDusk().getEnd(), sunTomorrow.getAstroDawn().getStart())); } // eclipse SunEclipse eclipse = sun.getEclipse(); MoonCalc mc = new MoonCalc(); double partial = mc.getEclipse(calendar, MoonCalc.ECLIPSE_TYPE_SUN, j, MoonCalc.ECLIPSE_MODE_PARTIAL); eclipse.setPartial(DateTimeUtils.toCalendar(partial)); double ring = mc.getEclipse(calendar, MoonCalc.ECLIPSE_TYPE_SUN, j, MoonCalc.ECLIPSE_MODE_RING); eclipse.setRing(DateTimeUtils.toCalendar(ring)); double total = mc.getEclipse(calendar, MoonCalc.ECLIPSE_TYPE_SUN, j, MoonCalc.ECLIPSE_MODE_TOTAL); eclipse.setTotal(DateTimeUtils.toCalendar(total)); return sun; } /** * Adds the specified days to the calendar. */ private Calendar addDays(Calendar calendar, int days) { Calendar cal = (Calendar) calendar.clone(); cal.add(Calendar.DAY_OF_MONTH, days); return cal; } // all the following methods are translated to java based on the javascript // calculations of http://www.suncalc.net private double getJulianCycle(double j, double lw) { return Math.round(j - J2000 - J0 - lw / (2 * Math.PI)); } private double getApproxSolarTransit(double ht, double lw, double n) { return J2000 + J0 + (ht + lw) / (2 * Math.PI) + n; } private double getSolarMeanAnomaly(double js) { return M0 + M1 * (js - J2000); } private double getEquationOfCenter(double m) { return C1 * Math.sin(m) + C2 * Math.sin(2 * m) + C3 * Math.sin(3 * m); } private double getEclipticLongitude(double m, double c) { return m + P + c + Math.PI; } private double getSolarTransit(double js, double m, double lsun) { return js + (J1 * Math.sin(m)) + (J2 * Math.sin(2 * lsun)); } private double getSunDeclination(double lsun) { return Math.asin(Math.sin(lsun) * Math.sin(E)); } private double getRightAscension(double lsun) { return Math.atan2(Math.sin(lsun) * Math.cos(E), Math.cos(lsun)); } private double getSiderealTime(double j, double lw) { return TH0 + TH1 * (j - J2000) - lw; } private double getAzimuth(double th, double a, double phi, double d) { double H = th - a; return Math.atan2(Math.sin(H), Math.cos(H) * Math.sin(phi) - Math.tan(d) * Math.cos(phi)); } private double getElevation(double th, double a, double phi, double d) { return Math.asin(Math.sin(phi) * Math.sin(d) + Math.cos(phi) * Math.cos(d) * Math.cos(th - a)); } private double getHourAngle(double h, double phi, double d) { return Math.acos((Math.sin(h) - Math.sin(phi) * Math.sin(d)) / (Math.cos(phi) * Math.cos(d))); } private double getSunsetJulianDate(double w0, double m, double Lsun, double lw, double n) { return getSolarTransit(getApproxSolarTransit(w0, lw, n), m, Lsun); } private double getSunriseJulianDate(double jtransit, double jset) { return jtransit - (jset - jtransit); } }