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feat: update source.
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@virtyaluk
virtyaluk committed Jan 8, 2020
1 parent e19c1fe commit 43c9f1c
Showing 1 changed file with 129 additions and 12 deletions.
141 changes: 129 additions & 12 deletions index.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -6,7 +6,7 @@
* Licensed under the MIT license.
*/

const { sin, cos, tan, asin, acos, atan2, PI, round } = Math;
const { sin, cos, tan, asin, acos, atan2, PI, round, floor, sqrt, abs } = Math;
const rad = PI / 180;
const e = rad * 23.4397;

Expand All @@ -19,6 +19,56 @@ const sunDiameter = 0.53 * rad;
const nauticalTwilightAngle = -6 * rad;
const astronomicalTwilightAngle = -12 * rad;
const darknessAngle = -18 * rad;
const zodiacs: { [key: string]: { sign: string, long: number }} = {
zodiac: {
sign: 'Aries',
long: 0
},
taurus: {
sign: 'Taurus',
long: 30
},
gemini: {
sign: 'Gemini',
long: 60
},
cancer: {
sign: 'Cancer',
long: 90
},
leo: {
sign: 'Leo',
long: 120
},
virgo: {
sign: 'Virgo',
long: 150
},
libra: {
sign: 'Libra',
long: 180
},
scorpio: {
sign: 'Scorpio',
long: 210
},
sagittarius: {
sign: 'Sagittarius',
long: 240
},
capricorn: {
sign: 'Capricorn',
long: 270
},
aquarius: {
sign: 'Aquarius',
long: 300
},
pisces: {
sign: 'Pisces',
long: 330
}
};

const toJulian = (date: Date): number => date.valueOf() / dayMills - 0.5 + julian1970;
const getDays = (date: Date): number => toJulian(date) - julian2000;
Expand Down Expand Up @@ -80,7 +130,17 @@ function getSunCoords(days: number): SunCoordinates {
};
}

function getMoonCoords(days: number): MoonCoordinates {
function normalize(v: number): number {
v = v - floor(v);

if (v < 0) {
v = v + 1;
}

return v;
}

function getMoonCoords(date: Date, days: number): MoonCoordinates {
const eclipticLong = rad * (218.316 + 13.176396 * days);
const meanAnomaly = rad * (134.963 + 13.064993 * days);
const meanDistance = rad * (93.272 + 13.229350 * days);
Expand All @@ -89,10 +149,44 @@ function getMoonCoords(days: number): MoonCoordinates {
const lat = rad * 5.128 * sin(meanDistance);
const distance = 385001 - 20905 * cos(meanAnomaly);

const year = date.getFullYear();
const month = date.getMonth()+1;
const day = date.getDate();
const yy = year - floor((12 - month) / 10);
let mm = month + 9;

if (mm >= 12) {
mm = mm - 12;
}

const k1 = floor(365.25 * (yy + 4712));
const k2 = floor(30.6 * mm + 0.5);
const k3 = floor(floor((yy / 100) + 49) * 0.75) - 38;
let jd = k1 + k2 + day + 59;

if (jd > 2299160) {
jd = jd - k3;
}

let ip = normalize((jd - 2451550.1) / 29.530588853);
ip = ip * 2 * PI;
const dp = 2 * PI * normalize((jd - 2451562.2) / 27.55454988);
const np = 2 * PI * normalize((jd - 2451565.2) / 27.212220817);
const latitude = 5.1 * sin(np);
const rp = normalize((jd - 2451555.8) / 27.321582241);
const longitude = 360 * rp + 6.3 * sin(dp) + 1.3 * sin(2 * ip - dp) + 0.7 * sin(2 * ip);
const zodiacSign = Object.keys(zodiacs)
.map(key => zodiacs[key])
.filter(zodiac => longitude >= zodiac.long && longitude < zodiac.long + 30)[0]
.sign;

return {
rightAscension: getRightAscension(long, lat),
declination: getDeclination(long, lat),
distance
distance,
latitude,
longitude,
zodiacSign
};
}

Expand Down Expand Up @@ -187,6 +281,9 @@ type MoonCoordinates = {
rightAscension: number;
declination: number;
distance: number;
latitude: number;
longitude: number;
zodiacSign: string;
};

/**
Expand All @@ -212,6 +309,21 @@ export type MoonPosition = {
* Parallactic angle of the moon in radians.
*/
parallacticAngle: number;

/**
* Moon ecliptic latitude.
*/
latitude: number;

/**
* Moon ecliptic magnitude.
*/
longitude: number;

/**
* Zodica sign the moon in.
*/
zodiacSign: string;
};

/**
Expand Down Expand Up @@ -368,11 +480,12 @@ function getSunTimes(date: Date, lat: number, lon: number): SunTimes {
* @return {MoonPosition} - Returns an object containing moon position info.
*/
function getMoonPosition(date: Date, lat: number, lon: number): MoonPosition {
date = date || new Date();
const lw = rad * -lon;
const phi = rad * lat;
const days = getDays(date || new Date());
const days = getDays(date);

const moonCoords = getMoonCoords(days);
const moonCoords = getMoonCoords(date, days);
const siderealTime = getSiderealTime(days, lw) - moonCoords.rightAscension;
let altitude = getAltitude(siderealTime, phi, moonCoords.declination);
const parallacticAngle = atan2(sin(siderealTime), tan(phi) * cos(moonCoords.declination) -
Expand All @@ -384,7 +497,10 @@ function getMoonPosition(date: Date, lat: number, lon: number): MoonPosition {
azimuth,
altitude,
distance: moonCoords.distance,
parallacticAngle
parallacticAngle,
latitude: moonCoords.latitude,
longitude: moonCoords.longitude,
zodiacSign: moonCoords.zodiacSign
};
}

Expand All @@ -395,9 +511,10 @@ function getMoonPosition(date: Date, lat: number, lon: number): MoonPosition {
* @return {MoonPhase} Returns an object containing moon phase info.
*/
function getMoonPhase(date: Date): MoonPhase {
date = date || new Date();
const days = getDays(date || new Date());
const sunCoords = getSunCoords(days);
const moonCoords = getMoonCoords(days);
const moonCoords = getMoonCoords(date, days);
const sunDistance = 149598000;

const phi = acos(sin(sunCoords.declination) * sin(moonCoords.declination) + cos(sunCoords.declination) *
Expand All @@ -409,7 +526,7 @@ function getMoonPhase(date: Date): MoonPhase {

return {
fraction: (1 + cos(inc)) / 2,
phase: 0.5 + 0.5 * inc * (angle < 0 ? -1 : 1) / Math.PI,
phase: 0.5 + 0.5 * inc * (angle < 0 ? -1 : 1) / PI,
angle: angle
};
}
Expand Down Expand Up @@ -441,15 +558,15 @@ function getMoonTimes(date: Date, lat: number, lon: number): MoonTimes {
roots = 0;

if (d >= 0) {
dx = Math.sqrt(d) / (Math.abs(a) * 2);
dx = sqrt(d) / (abs(a) * 2);
x1 = xe - dx;
x2 = xe + dx;

if (Math.abs(x1) <= 1) {
if (abs(x1) <= 1) {
roots++;
}

if (Math.abs(x2) <= 1) {
if (abs(x2) <= 1) {
roots++;
}

Expand Down Expand Up @@ -496,7 +613,7 @@ function getMoonTimes(date: Date, lat: number, lon: number): MoonTimes {

const sun = {
getPosition: getSunPosition,
getSunTimes: getSunTimes
getTimes: getSunTimes
};
const moon = {
getPosition: getMoonPosition,
Expand Down

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