SunCalc
Swift package to calculate the Sun and Moon positions


Description
SunCalc is a Swift package to calculate the sun position, sunlight phases (times for sunrise, sunset, dusk, etc.), moon position and lunar phase for the given location and time.
Most calculations are based on the formulas given in the excellent Astronomy Answers articles
about position of the sun
and the planets.
You can read about different twilight phases calculated by SunCalc
in the Twilight article on Wikipedia.
Usage
// get today's sunlight times for London
let date = Date()
let sunCalc = SunCalc.getTimes(date: date, latitude: 51.5, longitude: -0.1)
if let sunrise = sunCalc.sunrise {
debugPrint("sunrise: \(sunrise.formatted())")
}
if let sunset = sunCalc.sunset {
debugPrint("sunset: \(sunset.formatted())")
}
let sunPos = SunCalc.getSunPosition(timeAndDate: date, latitude: 51.5, longitude: -0.1)
let sunriseAzimuth = sunPos.azimuth * 180 / Constants.PI()
debugPrint("sunriseAzimuth: \(sunriseAzimuth)")
Reference
Sunlight times
SunCalc.getTimes(/*Date*/ date, /*Number*/ latitude, /*Number*/ longitude, /*Number (default=0)*/ height)
Returns an object with the following properties (each is a Date
object):
Property |
Description |
sunrise |
sunrise (top edge of the sun appears on the horizon) |
sunriseEnd |
sunrise ends (bottom edge of the sun touches the horizon) |
goldenHourEnd |
morning golden hour (soft light, best time for photography) ends |
solarNoon |
solar noon (sun is in the highest position) |
goldenHour |
evening golden hour starts |
sunsetStart |
sunset starts (bottom edge of the sun touches the horizon) |
sunset |
sunset (sun disappears below the horizon, evening civil twilight starts) |
dusk |
dusk (evening nautical twilight starts) |
nauticalDusk |
nautical dusk (evening astronomical twilight starts) |
night |
night starts (dark enough for astronomical observations) |
nadir |
nadir (darkest moment of the night, sun is in the lowest position) |
nightEnd |
night ends (morning astronomical twilight starts) |
nauticalDawn |
nautical dawn (morning nautical twilight starts) |
dawn |
dawn (morning nautical twilight ends, morning civil twilight starts) |
SunCalc.addTime(/*Number*/ angleInDegrees, /*String*/ morningName, /*String*/ eveningName)
Adds a custom time when the sun reaches the given angle to results returned by SunCalc.getTimes
.
SunCalc.times
property contains all currently defined times.
Sun position
SunCalc.getPosition(/*Date*/ timeAndDate, /*Number*/ latitude, /*Number*/ longitude)
Returns an object with the following properties:
altitude
: sun altitude above the horizon in radians,
e.g. 0
at the horizon and PI/2
at the zenith (straight over your head)
azimuth
: sun azimuth in radians (direction along the horizon, measured from south to west),
e.g. 0
is south and Math.PI * 3/4
is northwest
Moon position
SunCalc.getMoonPosition(/*Date*/ timeAndDate, /*Number*/ latitude, /*Number*/ longitude)
Returns an object with the following properties:
altitude
: moon altitude above the horizon in radians
azimuth
: moon azimuth in radians
distance
: distance to moon in kilometers
parallacticAngle
: parallactic angle of the moon in radians
Moon illumination
SunCalc.getMoonIllumination(/*Date*/ timeAndDate)
Returns an object with the following properties:
fraction
: illuminated fraction of the moon; varies from 0.0
(new moon) to 1.0
(full moon)
phase
: moon phase; varies from 0.0
to 1.0
, described below
angle
: midpoint angle in radians of the illuminated limb of the moon reckoned eastward from the north point of the disk;
the moon is waxing if the angle is negative, and waning if positive
Moon phase value should be interpreted like this:
Phase |
Name |
0 |
New Moon |
|
Waxing Crescent |
0.25 |
First Quarter |
|
Waxing Gibbous |
0.5 |
Full Moon |
|
Waning Gibbous |
0.75 |
Last Quarter |
|
Waning Crescent |
By subtracting the parallacticAngle
from the angle
one can get the zenith angle of the moons bright limb (anticlockwise).
The zenith angle can be used do draw the moon shape from the observers perspective (e.g. moon lying on its back).
Moon rise and set times
SunCalc.getMoonTimes(/*Date*/ date, /*Number*/ latitude, /*Number*/ longitude[, inUTC])
Returns an object with the following properties:
rise
: moonrise time as Date
set
: moonset time as Date
alwaysUp
: true
if the moon never rises/sets and is always above the horizon during the day
alwaysDown
: true
if the moon is always below the horizon
By default, it will search for moon rise and set during local user’s day (frou 0 to 24 hours).
If inUTC
is set to true, it will instead search the specified date from 0 to 24 UTC hours.
License
This project is based on the source code https://github.com/shanus/suncalc-swift written by Shaun Meredith, which is based on the original Javascript suncalc by Vladimir Agafonkin (“mourner”) available at https://github.com/mourner/suncalc
SunCalc
Swift package to calculate the Sun and Moon positions
Description
SunCalc is a Swift package to calculate the sun position, sunlight phases (times for sunrise, sunset, dusk, etc.), moon position and lunar phase for the given location and time.
Most calculations are based on the formulas given in the excellent Astronomy Answers articles about position of the sun and the planets. You can read about different twilight phases calculated by SunCalc in the Twilight article on Wikipedia.
Usage
Reference
Sunlight times
Returns an object with the following properties (each is a
Date
object):sunrise
sunriseEnd
goldenHourEnd
solarNoon
goldenHour
sunsetStart
sunset
dusk
nauticalDusk
night
nadir
nightEnd
nauticalDawn
dawn
Adds a custom time when the sun reaches the given angle to results returned by
SunCalc.getTimes
.SunCalc.times
property contains all currently defined times.Sun position
Returns an object with the following properties:
altitude
: sun altitude above the horizon in radians, e.g.0
at the horizon andPI/2
at the zenith (straight over your head)azimuth
: sun azimuth in radians (direction along the horizon, measured from south to west), e.g.0
is south andMath.PI * 3/4
is northwestMoon position
Returns an object with the following properties:
altitude
: moon altitude above the horizon in radiansazimuth
: moon azimuth in radiansdistance
: distance to moon in kilometersparallacticAngle
: parallactic angle of the moon in radiansMoon illumination
Returns an object with the following properties:
fraction
: illuminated fraction of the moon; varies from0.0
(new moon) to1.0
(full moon)phase
: moon phase; varies from0.0
to1.0
, described belowangle
: midpoint angle in radians of the illuminated limb of the moon reckoned eastward from the north point of the disk; the moon is waxing if the angle is negative, and waning if positiveMoon phase value should be interpreted like this:
By subtracting the
parallacticAngle
from theangle
one can get the zenith angle of the moons bright limb (anticlockwise). The zenith angle can be used do draw the moon shape from the observers perspective (e.g. moon lying on its back).Moon rise and set times
Returns an object with the following properties:
rise
: moonrise time asDate
set
: moonset time asDate
alwaysUp
:true
if the moon never rises/sets and is always above the horizon during the dayalwaysDown
:true
if the moon is always below the horizonBy default, it will search for moon rise and set during local user’s day (frou 0 to 24 hours). If
inUTC
is set to true, it will instead search the specified date from 0 to 24 UTC hours.License
This project is based on the source code https://github.com/shanus/suncalc-swift written by Shaun Meredith, which is based on the original Javascript suncalc by Vladimir Agafonkin (“mourner”) available at https://github.com/mourner/suncalc