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Merge pull request #34 from mannylopez/adopt-moontool
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Adopt MoonTool formula for calculating moon phase
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@mannylopez
mannylopez authored Jul 13, 2024
2 parents b93dd90 + 3be8bbc commit 50b5dfd
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336 changes: 174 additions & 162 deletions Sources/TinyMoon/TinyMoon+AstronomicalConstant.swift
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28 changes: 28 additions & 0 deletions Sources/TinyMoon/TinyMoon+MoonDetail.swift
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// Created by manny_lopez on 7/12/24.

import Foundation

// MARK: - TinyMoon + MoonDetail

extension TinyMoon {

struct MoonDetail {
let julianDay: Double
/// Number of days elapsed into the synodic cycle, represented as a fraction
let daysElapsedInCycle: Double
/// Age of the moon in days, minutes, hours
let ageOfMoon: (days: Int, hours: Int, minutes: Int)
/// Illuminated portion of the Moon, where 0.0 = new and 0.99 = full
let illuminatedFraction: Double
/// Distance of moon from the center of the Earth, in kilometers
let distanceFromCenterOfEarth: Double
/// Phase of the Moon, represented as a fraction
///
/// Varies between `0.0` to `0.99`.
/// `0.0` new moon,
/// `0.25` first quarter,
/// `0.5` full moon,
/// `0.75` last quarter
let phase: Double
}
}
2 changes: 2 additions & 0 deletions Sources/TinyMoon/TinyMoon.swift
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Expand Up @@ -57,6 +57,7 @@ public enum TinyMoon {
day: Int,
hour: Int = 00,
minute: Int = 00,
second: Int = 00,
timeZone: TimeZone = TimeZoneOption.createTimeZone(timeZone: .utc))
-> Date
{
Expand All @@ -66,6 +67,7 @@ public enum TinyMoon {
components.day = day
components.hour = hour
components.minute = minute
components.second = second
components.timeZone = timeZone

return Calendar.current.date(from: components)!
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186 changes: 52 additions & 134 deletions Tests/TinyMoonTests/AstronomicalConstantTests.swift
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Expand Up @@ -76,158 +76,76 @@ final class AstronomicalConstantTests: XCTestCase {
XCTAssertEqual(julianDay, 2459814.4993055556)
}

func test_astronomicalConstant_daysSinceJ2000() {
// 1
var date = TinyMoon.formatDate(year: 2004, month: 01, day: 1)
var julianDay = TinyMoon.AstronomicalConstant.julianDay(date)
XCTAssertEqual(julianDay, 2453005.5000)

var daysSinceJ2000 = TinyMoon.AstronomicalConstant.daysSinceJ2000(from: julianDay)
XCTAssertEqual(daysSinceJ2000, 1460.5)

// 2
date = TinyMoon.formatDate(year: 2022, month: 08, day: 22, hour: 23, minute: 59)
julianDay = TinyMoon.AstronomicalConstant.julianDay(date)
XCTAssertEqual(julianDay, 2459814.4993055556)

daysSinceJ2000 = TinyMoon.AstronomicalConstant.daysSinceJ2000(from: julianDay)
XCTAssertEqual(daysSinceJ2000, 8269.499305555597)
}

func test_astronomicalConstant_moonCoordinates() {
let date = TinyMoon.formatDate(year: 2004, month: 01, day: 1)
let julianDay = TinyMoon.AstronomicalConstant.julianDay(date)
let moonCoordinates = TinyMoon.AstronomicalConstant.moonCoordinates(julianDay: julianDay)

// Test values taken from https://aa.quae.nl/en/reken/hemelpositie.html#4
// XCTAssertEqual(moonCoordinates.L, 339.683699626709) // 22.44 degrees
// XCTAssertEqual(moonCoordinates.M, 335.3891934066859) // 136.39 degrees
// XCTAssertEqual(moonCoordinates.F, 338.8510958397388) // 334.74 degrees
//
// XCTAssertEqual(moonCoordinates.longitude, 339.7594152822631) // 0.46740869456428196793
// XCTAssertEqual(moonCoordinates.latitude, -0.038195520939872045) // -0.038195520939775448599

XCTAssertEqual(moonCoordinates.declination, 0.14456842408751425)
XCTAssertEqual(moonCoordinates.rightAscension, 0.4475918797699177)
XCTAssertEqual(moonCoordinates.distance, 400136.10760520655)
}

func test_astronomicalConstant_declination() {
// Test values taken from https://aa.quae.nl/en/reken/hemelpositie.html#1_7
let longitude = TinyMoon.AstronomicalConstant.degreesToRadians(168.737)
let latitude = TinyMoon.AstronomicalConstant.degreesToRadians(1.208)
let declination = TinyMoon.AstronomicalConstant.declination(longitude: longitude, latitude: latitude)

XCTAssertEqual(declination, TinyMoon.AstronomicalConstant.degreesToRadians(5.567), accuracy: 1e-5)

XCTAssertEqual(declination, 0.09717015472346271, accuracy: 1e-5)
}

func test_astronomicalConstant_rightAscension() {
// Test values taken from https://aa.quae.nl/en/reken/hemelpositie.html#1_7
let longitude = TinyMoon.AstronomicalConstant.degreesToRadians(168.737)
let latitude = TinyMoon.AstronomicalConstant.degreesToRadians(1.208)
let rightAscension = TinyMoon.AstronomicalConstant.rightAscension(longitude: longitude, latitude: latitude)

XCTAssertEqual(rightAscension, TinyMoon.AstronomicalConstant.degreesToRadians(170.20), accuracy: 0.0015)

XCTAssertEqual(rightAscension, 2.969160475404514)
}

func test_astronomicalConstant_solarMeanAnomaly() {
var date = TinyMoon.formatDate(year: 2004, month: 01, day: 1)
var julianDay = TinyMoon.AstronomicalConstant.julianDay(date)
var solarMeanAnomaly = TinyMoon.AstronomicalConstant.solarMeanAnomaly(julianDay: julianDay)
XCTAssertEqual(solarMeanAnomaly, 31.363537143773254)

date = TinyMoon.formatDate(year: 2005, month: 02, day: 2)
julianDay = TinyMoon.AstronomicalConstant.julianDay(date)
solarMeanAnomaly = TinyMoon.AstronomicalConstant.solarMeanAnomaly(julianDay: julianDay)
XCTAssertEqual(solarMeanAnomaly, 38.20992120161531)

date = TinyMoon.formatDate(year: 2006, month: 03, day: 10)
julianDay = TinyMoon.AstronomicalConstant.julianDay(date)
solarMeanAnomaly = TinyMoon.AstronomicalConstant.solarMeanAnomaly(julianDay: julianDay)
XCTAssertEqual(solarMeanAnomaly, 45.107911169441095)

date = TinyMoon.formatDate(year: 2006, month: 03, day: 10, hour: 6)
julianDay = TinyMoon.AstronomicalConstant.julianDay(date)
solarMeanAnomaly = TinyMoon.AstronomicalConstant.solarMeanAnomaly(julianDay: julianDay)
XCTAssertEqual(solarMeanAnomaly, 45.11221166193974)

date = TinyMoon.formatDate(year: 2016, month: 04, day: 15, hour: 6)
julianDay = TinyMoon.AstronomicalConstant.julianDay(date)
solarMeanAnomaly = TinyMoon.AstronomicalConstant.solarMeanAnomaly(julianDay: julianDay)
XCTAssertEqual(solarMeanAnomaly, 108.57027897193804)

date = TinyMoon.formatDate(year: 2016, month: 04, day: 15, hour: 6, minute: 5)
julianDay = TinyMoon.AstronomicalConstant.julianDay(date)
solarMeanAnomaly = TinyMoon.AstronomicalConstant.solarMeanAnomaly(julianDay: julianDay)
XCTAssertEqual(solarMeanAnomaly, 108.57033870099696)

date = TinyMoon.formatDate(year: 2016, month: 04, day: 15, hour: 6, minute: 30)
julianDay = TinyMoon.AstronomicalConstant.julianDay(date)
solarMeanAnomaly = TinyMoon.AstronomicalConstant.solarMeanAnomaly(julianDay: julianDay)
XCTAssertEqual(solarMeanAnomaly, 108.57063734631559)

date = TinyMoon.formatDate(year: 2020, month: 10, day: 20, hour: 9, minute: 25)
julianDay = TinyMoon.AstronomicalConstant.julianDay(date)
solarMeanAnomaly = TinyMoon.AstronomicalConstant.solarMeanAnomaly(julianDay: julianDay)
XCTAssertEqual(solarMeanAnomaly, 136.93877638455712)
}

func test_astronomicalConstant_eclipticLongitude() {
let date = TinyMoon.formatDate(year: 2004, month: 01, day: 1)
let julianDay = TinyMoon.AstronomicalConstant.julianDay(date)
let solarMeanAnomaly = TinyMoon.AstronomicalConstant.solarMeanAnomaly(julianDay: julianDay)
let eclipticLongitude = TinyMoon.AstronomicalConstant.eclipticLongitude(solarMeanAnomaly: solarMeanAnomaly)
XCTAssertEqual(eclipticLongitude, 36.299935502913485)
}

func test_astronomicalConstant_sunCoordinates() {
let date = TinyMoon.formatDate(year: 2004, month: 01, day: 1)
let julianDay = TinyMoon.AstronomicalConstant.julianDay(date)
let sunCoordinates = TinyMoon.AstronomicalConstant.sunCoordinates(julianDay: julianDay)

XCTAssertEqual(sunCoordinates.declination, -0.4027393891133564)
XCTAssertEqual(sunCoordinates.rightAscension, -1.3840823935200117)
}

func test_astronomicalConstant_getMoonPhase() {
func test_astronomicalConstant_getMoonPhase_moonDetail() {
// Full moon
var date = TinyMoon.formatDate(year: 2024, month: 06, day: 22)
var julianDay = TinyMoon.AstronomicalConstant.julianDay(date)
var moonPhase = TinyMoon.AstronomicalConstant.getMoonPhase(julianDay: julianDay)
var moonDetail = TinyMoon.AstronomicalConstant.getMoonPhase(julianDay: julianDay)

XCTAssertEqual(moonPhase.illuminatedFraction, 0.9978873506056865)
XCTAssertEqual(moonPhase.phase, 0.48536418607701615)
XCTAssertEqual(moonPhase.angle, -2.8703533722710577)
XCTAssertEqual(moonDetail.julianDay, 2460483.5)
XCTAssertEqual(moonDetail.daysElapsedInCycle, 14.716658695349988)
XCTAssertEqual(moonDetail.ageOfMoon.days, 14)
XCTAssertEqual(moonDetail.ageOfMoon.hours, 17)
XCTAssertEqual(moonDetail.ageOfMoon.minutes, 11)
XCTAssertEqual(moonDetail.illuminatedFraction, 0.9999732292206713)
XCTAssertEqual(moonDetail.distanceFromCenterOfEarth, 382758.57898868265)
XCTAssertEqual(moonDetail.phase, 0.49835304181785745)

// New moon
date = TinyMoon.formatDate(year: 2024, month: 07, day: 06, hour: 12, minute: 37)
julianDay = TinyMoon.AstronomicalConstant.julianDay(date)
moonPhase = TinyMoon.AstronomicalConstant.getMoonPhase(julianDay: julianDay)
moonDetail = TinyMoon.AstronomicalConstant.getMoonPhase(julianDay: julianDay)

XCTAssertEqual(moonPhase.illuminatedFraction, 0.007424715413253902)
XCTAssertEqual(moonPhase.phase, 0.02746179502131707)
XCTAssertEqual(moonPhase.angle, -1.9356676727903563)
XCTAssertEqual(moonDetail.julianDay, 2460498.0256944443)
XCTAssertEqual(moonDetail.daysElapsedInCycle, 0.5665252000982685)
XCTAssertEqual(moonDetail.ageOfMoon.days, 0)
XCTAssertEqual(moonDetail.ageOfMoon.hours, 13)
XCTAssertEqual(moonDetail.ageOfMoon.minutes, 35)
XCTAssertEqual(moonDetail.illuminatedFraction, 0.0036280068150687517)
XCTAssertEqual(moonDetail.distanceFromCenterOfEarth, 390943.47575863753)
XCTAssertEqual(moonDetail.phase, 0.019184351732275336)

// First quarter
date = TinyMoon.formatDate(year: 2024, month: 08, day: 12, hour: 15, minute: 18)
julianDay = TinyMoon.AstronomicalConstant.julianDay(date)
moonPhase = TinyMoon.AstronomicalConstant.getMoonPhase(julianDay: julianDay)
moonDetail = TinyMoon.AstronomicalConstant.getMoonPhase(julianDay: julianDay)

XCTAssertEqual(moonPhase.illuminatedFraction, 0.5105081080980992)
XCTAssertEqual(moonPhase.phase, 0.25334508096684466)
XCTAssertEqual(moonPhase.angle, -1.2995618398922297)
XCTAssertEqual(moonDetail.julianDay, 2460535.1375)
XCTAssertEqual(moonDetail.daysElapsedInCycle, 7.398740016912393)
XCTAssertEqual(moonDetail.ageOfMoon.days, 7)
XCTAssertEqual(moonDetail.ageOfMoon.hours, 9)
XCTAssertEqual(moonDetail.ageOfMoon.minutes, 34)
XCTAssertEqual(moonDetail.illuminatedFraction, 0.5017120238066795)
XCTAssertEqual(moonDetail.distanceFromCenterOfEarth, 398519.14701141417)
XCTAssertEqual(moonDetail.phase, 0.2505449551679033)

// Last quarter
date = TinyMoon.formatDate(year: 2024, month: 08, day: 26, hour: 09, minute: 25)
julianDay = TinyMoon.AstronomicalConstant.julianDay(date)
moonPhase = TinyMoon.AstronomicalConstant.getMoonPhase(julianDay: julianDay)
moonDetail = TinyMoon.AstronomicalConstant.getMoonPhase(julianDay: julianDay)

XCTAssertEqual(moonDetail.julianDay, 2460548.892361111)
XCTAssertEqual(moonDetail.daysElapsedInCycle, 22.14959253613732)
XCTAssertEqual(moonDetail.ageOfMoon.days, 22)
XCTAssertEqual(moonDetail.ageOfMoon.hours, 3)
XCTAssertEqual(moonDetail.ageOfMoon.minutes, 35)
XCTAssertEqual(moonDetail.illuminatedFraction, 0.49982435665155855)
XCTAssertEqual(moonDetail.distanceFromCenterOfEarth, 372205.09027872747)
XCTAssertEqual(moonDetail.phase, 0.7500559090154013)
}

func test_moontool() {
// Test taken from https://www.fourmilab.ch/moontoolw/
let utcTimeZone = TinyMoon.TimeZoneOption.createTimeZone(timeZone: .utc)
let date = TinyMoon.formatDate(year: 1999, month: 07, day: 20, hour: 20, minute: 17, second: 40, timeZone: utcTimeZone)
let julianDay = TinyMoon.AstronomicalConstant.julianDay(date)
let moonDetail = TinyMoon.AstronomicalConstant.getMoonPhase(julianDay: julianDay)
XCTAssertEqual(moonDetail.julianDay, 2451380.345601852)
XCTAssertEqual(moonDetail.ageOfMoon.days, 7)
XCTAssertEqual(moonDetail.ageOfMoon.hours, 19)
XCTAssertEqual(moonDetail.ageOfMoon.minutes, 30)
XCTAssertEqual(round(moonDetail.illuminatedFraction * 100), 55)
XCTAssertEqual(round(moonDetail.distanceFromCenterOfEarth), 402026)

XCTAssertEqual(moonPhase.illuminatedFraction, 0.5115383513011658)
XCTAssertEqual(moonPhase.phase, 0.7463269026530461)
XCTAssertEqual(moonPhase.angle, 1.3632094278875226)
}
}
4 changes: 2 additions & 2 deletions Tests/TinyMoonTests/Helpers/MoonTestHelper.swift
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Expand Up @@ -200,9 +200,9 @@ extension MoonTestHelper {
/// *🌗 |23🌘 |24🌘 |25🌘 |26🌘 |27🌘 |28🌘 |
/// 29🌘 | *🌑 |31🌒 |
/// ```
static func prettyPrintCalendarForYear(_ year: Int) {
static func prettyPrintCalendarForYear(_ year: Int, timeZone: TimeZone = utcTimeZone) {
for month in MonthTestHelper.Month.allCases {
MoonTestHelper.prettyPrintMoonCalendar(month: month, year: year)
MoonTestHelper.prettyPrintMoonCalendar(month: month, year: year, timeZone: timeZone)
}
}

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