Sun calculation js library which is fully based on formula from http://aa.quae.nl/en/reken/zonpositie.html
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284 lines
9.9 KiB
284 lines
9.9 KiB
/*
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MIT License
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Copyright (c) 2018 Robby Muhammad Nst
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Permission is hereby granted, free of charge, to any person obtaining a copy
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of this software and associated documentation files (the "Software"), to deal
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in the Software without restriction, including without limitation the rights
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to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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copies of the Software, and to permit persons to whom the Software is
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furnished to do so, subject to the following conditions:
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The above copyright notice and this permission notice shall be included in all
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copies or substantial portions of the Software.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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SOFTWARE.
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*/
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const JD1970 = 2440588;
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const JD2000 = 2451545;
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const earthC_coefficient_component = {
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C1: 1.9148,
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C2: 0.0200,
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C3: 0.0003,
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C4: 0,
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C5: 0,
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C6: 0,
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EC: 0.0000
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}
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const earth_perihelion = 102.9373;
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const earth_obliquity = 23.4393 * (Math.PI / 180);
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const earth_obliquity_degrees = 23.4393;
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const earth_sideral_time = {
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at_zero_long: 280.1470,
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rate_of_change: 360.9856235
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};
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class Sunpositioning {
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/* Earth */
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/* J0: 0.0009
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J1: 0.0053
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J2: -0.0068
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J3: 1 */
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/*
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h0 dSun sin(h0)
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Mercury −0.69 1.38 −0.0120
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Venus −0.37 0.74 −0.0064
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Earth −0.83 0.53 −0.0146
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Mars −0.17 0.35 −0.0031
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*/
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/*
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M0 M1
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Mercury 174.7948 4.09233445
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Venus 50.4161 1.60213034
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Earth 357.5291 0.98560028
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Mars 19.3730 0.52402068
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Jupiter 20.0202 0.08308529
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Saturn 317.0207 0.03344414
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Uranus 141.0498 0.01172834
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Neptune 256.2250 0.00598103
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Pluto 14.882 0.00396
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*/
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constructor(){}
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/**
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@param {Date} date user current date
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@param {number} lat user latitude
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@param {number} long user longitude
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@returns {Object} sun postiion, date, observe location, sunrise&sunset, solar transit, hour angle, RA and clientJD
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*/
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getSunInformation(date, lat, long) {
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this.CLIENT_JD = this.dateToJD(date);
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this.CLIENT_LATITUDE = lat;
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this.CLIENT_LONGITUDE = long;
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this.CLIENT_lw = -long;
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let position = this.getSunPosition();
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return {
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sun_position: {
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azimuth: position.azimuth.degrees,
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altitude: position.altitude.degrees
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},
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date: this.jdToDate(this.CLIENT_JD).toString(),
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observe_location: {
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latitude: this.CLIENT_LATITUDE,
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longitude: this.CLIENT_LONGITUDE
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},
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sunrise: this.jdToDate(this.sunriseandsunset(this.CLIENT_JD).sunrise).toString(),
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sunset: this.jdToDate(this.sunriseandsunset(this.CLIENT_JD).sunset).toString(),
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solar_transit: this.solarTransit(this.CLIENT_JD),
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hour_angle: this.getHourAngle(this.CLIENT_JD),
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right_ascension: this.rightAscension(this.CLIENT_JD),
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clientJD: this.CLIENT_JD,
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};
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}
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/**
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* @param {Date} date date
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* @returns {number} JulianDate of the given date
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*/
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dateToJD(date) {
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return date.valueOf() / ( 1000 * 60 * 60 * 24 ) - 0.5 + JD1970;
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}
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/**
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*
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* @param {number} jd JulianDate
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* @returns {number} date from given JulianDate
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*/
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jdToDate(jd) {
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return new Date((jd + 0.5 - JD1970) * ( 1000 * 60 * 60 * 24 ) )
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}
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/**
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*
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* @param {number} jd
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*/
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equation_of_center(jd) {
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/*
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the C4 - C6 are 0, so I just calculate for Coefficient 1 - 3.
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*/
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let results = earthC_coefficient_component.C1 * Math.sin(this.earthMeanAnomaly(jd).rad) +
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earthC_coefficient_component.C2 * Math.sin(2 * this.earthMeanAnomaly(jd).rad) +
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earthC_coefficient_component.C3 * Math.sin(3 * this.earthMeanAnomaly(jd).rad);
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return {
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degrees: results,
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rad: results * (Math.PI / 180)
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};
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}
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/**
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*
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* @param {number} jd JulianDate
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* @returns {Object} earth mean anomaly in degrees and radiant
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*/
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earthMeanAnomaly(jd) {
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return {
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degrees: ( 357.5291 + 0.98560028 * ( jd - JD2000 ) ) % 360,
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rad: (( 357.5291 + 0.98560028 * ( jd - JD2000 ) ) % 360) * (Math.PI / 180)
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}
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}
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/**
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*
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* @param {number} jd JulianDate
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* @returns {Object} earth true anomaly in degrees and radiant
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*/
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earthTrueAnomaly(jd) {
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let results = this.equation_of_center(jd).degrees + this.earthMeanAnomaly(jd).degrees;
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return {
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degrees: results,
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rad: results * (Math.PI / 180)
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}
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}
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/**
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*
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* @param {number} jd JulianDate
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* @returns {Object} ecliptic Longitude by given JulianDate in degrees and radiant
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*/
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eclipticLongtitude(jd) {
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let true_anomaly = this.earthTrueAnomaly(jd);
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let results = (true_anomaly.degrees + earth_perihelion + 180) % 360;
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return {
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degrees: results,
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rad: results * (Math.PI / 180)
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};
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}
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/**
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*
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* @param {number} jd JulianDate
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* @returns {Object} rightascension by the given JulianDate in degrees and radiant
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*/
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rightAscension(jd) {
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let ecliptic_longitude = this.eclipticLongtitude(jd);
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let results = Math.atan2(Math.sin(ecliptic_longitude.rad) * Math.cos(earth_obliquity), Math.cos(ecliptic_longitude.rad));
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return {
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degrees: results / (Math.PI / 180),
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rad: results
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};
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}
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/**
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*
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* @param {number} jd JulianDate
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* @returns {Object} declination by the given JulianDate in degrees and radiant
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*/
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declination(jd) {
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let ecliptic_longitude = this.eclipticLongtitude(jd);
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let results = Math.asin(Math.sin(ecliptic_longitude.rad) * Math.sin(earth_obliquity));
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return {
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degrees: results / (Math.PI / 180),
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rad: results
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};
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}
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/**
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*
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* @param {number} jd JulianDate
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* @returns {number} Sideral time by the given JulianDate in degrees
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*/
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sideraltime(jd) {
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let results = (earth_sideral_time.at_zero_long + earth_sideral_time.rate_of_change * (jd - JD2000) - (this.CLIENT_lw)) % 360;
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return results;
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}
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/**
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*
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* @param {number} jd JulianDate
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* @return {number} HourAngle in degrees by the given Julian date
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*/
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getHourAngle(jd) {
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return this.sideraltime(jd) - this.rightAscension(jd).degrees;
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}
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/**
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* Please don't call it by itself. You could get this value in other ways like
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* call the getSunInformation function.
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* @returns {Object} Return the azimuth and altitude of the sun
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*/
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getSunPosition() {
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return {
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azimuth: {
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rad: Math.atan2(Math.sin(this.getHourAngle(this.CLIENT_JD) * Math.PI / 180),
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Math.cos(this.getHourAngle(this.CLIENT_JD) * Math.PI / 180) * Math.sin(this.CLIENT_LATITUDE * Math.PI / 180) - Math.tan(this.declination(this.CLIENT_JD).rad) * Math.cos(this.CLIENT_LATITUDE * Math.PI / 180)),
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degrees: Math.atan2(Math.sin(this.getHourAngle(this.CLIENT_JD) * Math.PI / 180),
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Math.cos(this.getHourAngle(this.CLIENT_JD) * Math.PI / 180) * Math.sin(this.CLIENT_LATITUDE * Math.PI / 180) -
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Math.tan(this.declination(this.CLIENT_JD).rad) * Math.cos(this.CLIENT_LATITUDE * Math.PI / 180)) / (Math.PI / 180)
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},
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altitude: {
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rad: Math.asin(Math.sin(this.CLIENT_LATITUDE * (Math.PI / 180)) * Math.sin(this.declination(this.CLIENT_JD).rad) +
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Math.cos(this.CLIENT_LATITUDE * Math.PI / 180) * Math.cos(this.declination(this.CLIENT_JD).rad) * Math.cos(this.getHourAngle(this.CLIENT_JD) * Math.PI / 180)),
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degrees: Math.asin(Math.sin(this.CLIENT_LATITUDE * (Math.PI / 180)) * Math.sin(this.declination(this.CLIENT_JD).rad) +
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Math.cos(this.CLIENT_LATITUDE * Math.PI / 180) * Math.cos(this.declination(this.CLIENT_JD).rad) * Math.cos(this.getHourAngle(this.CLIENT_JD) * Math.PI / 180)) / (Math.PI / 180)
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}
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}
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}
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/**
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*
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* @param {number} jd JulianDate
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* @return {number} solarTransit in JulianDate
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*/
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solarTransit(jd) {
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let lw = this.CLIENT_lw;
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let _JD2000 = JD2000
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function nx() { return ((jd - _JD2000 - 0.0009) / 1 - (lw / 360)); }
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let n = Math.round(nx());
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function JDX() { return jd + 1 * ( n - nx() ); }
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let M = this.earthMeanAnomaly(JDX()).degrees;
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let L = (M + earth_perihelion + 180) % 360;
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let JDtmp = JDX() + 0.0053 * Math.sin(M * Math.PI / 180) - 0.0068 * Math.sin(2 * (L * (Math.PI / 180)));
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return JDtmp - (0 / 360 ) * 1;
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}
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/**
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*
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* @param {number} jd JulianDate
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* @return {Object} sunrise and sunset in JulianDate
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*/
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sunriseandsunset(jd) {
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let jd_from_approx_transit = this.solarTransit(jd);
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let sundeclination = this.declination(jd_from_approx_transit);
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let Ht = Math.acos((-0.0146 - Math.sin(this.CLIENT_LATITUDE * Math.PI / 180) * Math.sin(sundeclination.rad)) /
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Math.cos(this.CLIENT_LATITUDE * Math.PI / 180) * Math.cos(sundeclination.rad));
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return {
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sunrise: jd_from_approx_transit - ((Ht / (Math.PI / 180)) / 360) * 1,
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sunset: jd_from_approx_transit + ((Ht / (Math.PI / 180)) / 360) * 1
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}
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}
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}
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module.exports = new Sunpositioning();
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