Package 'suncalc'

Title: Compute Sun Position, Sunlight Phases, Moon Position and Lunar Phase
Description: Get 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 Astronomy Answers articles about position of the sun and the planets : <https://www.aa.quae.nl/en/reken/zonpositie.html>.
Authors: Benoit Thieurmel [aut, cre] (R interface), Achraf Elmarhraoui [aut] (R interface)
Maintainer: Benoit Thieurmel <[email protected]>
License: GPL-2 | file LICENSE
Version: 0.5.3
Built: 2026-07-15 14:48:19 UTC
Source: https://github.com/datastorm-open/suncalc

Help Index

Get Moon illumination

Description

Get Moon illumination

Usage

getMoonIllumination(date = Sys.Date(), keep = c("fraction", "phase", "angle"))

Arguments

date

Single or multiple DateTime. Can be a Date (YYYY-MM-DD), a character in UTC (YYYY-MM-DD HH:mm:ss) or a POSIXct
keep

character. Vector of variables to keep. See Details

Details

Computes 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:

0 New Moon
Waxing Crescent
0.25 First Quarter
Waxing Gibbous
0.5 Full Moon
Waning Gibbous
0.75 Last Quarter
Waning Crescent
1 New Moon

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).

Value

data.frame

See Also

Other suncalc functions: getMoonPosition(), getMoonTimes(), getSunlightPosition(), getSunlightTimes()

Examples

# one date
getMoonIllumination(date = Sys.Date())

# in character
getMoonIllumination(date = c("2017-05-12", "2017-05-12 00:00:00"), 
  keep = c("fraction", "phase"))

# in POSIXct
getMoonIllumination(date = as.POSIXct("2017-05-12 00:00:00", tz = "UTC"))
getMoonIllumination(date = as.POSIXct("2017-05-12 02:00:00", tz = "CET"))

date <- seq(ISOdate(2009,1,1), ISOdate(2010,1,1), "hours")
date_cet <- date
attr(date_cet, "tzone") <- "CET"
res <- getMoonIllumination(date = date_cet)

Get Moon position

Description

Get Moon position

Usage

getMoonPosition(
  date = NULL,
  lat = NULL,
  lon = NULL,
  data = NULL,
  keep = c("altitude", "azimuth", "distance", "parallacticAngle")
)

Arguments

date

Single or multiple DateTime. Can be a Date (YYYY-MM-DD), a character in UTC (YYYY-MM-DD HH:mm:ss) or a POSIXct
lat

numeric. Single latitude
lon

numeric. Single longitude
data

data.frame. Alternative to use date, lat, lon for passing multiple coordinates
keep

character. Vector of variables to keep. See Details

Details

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

Value

data.frame

See Also

Other suncalc functions: getMoonIllumination(), getMoonTimes(), getSunlightPosition(), getSunlightTimes()

Examples

# one date
getMoonPosition(date = Sys.Date(), lat = 50.1, lon = 1.83)

# in character
getMoonPosition(date = c("2017-05-12", "2017-05-12 00:00:00"), 
    lat = 50.1, lon = 1.83)

# in POSIXct
getMoonPosition(date = as.POSIXct("2017-05-12 00:00:00", tz = "UTC"),
    lat = 50.1, lon = 1.83)
getMoonPosition(date = as.POSIXct("2017-05-12 02:00:00", tz = "CET"),
    lat = 50.1, lon = 1.83)

# multiple date + subset
getMoonPosition(date = seq.Date(Sys.Date()-9, Sys.Date(), by = 1), 
  keep = c("altitude", "azimuth"), 
  lat = 50.1, lon = 1.83)
  
# multiple coordinates
data <- data.frame(date = seq.Date(Sys.Date()-9, Sys.Date(), by = 1), 
    lat = c(rep(50.1, 10), rep(49, 10)), 
    lon = c(rep(1.83, 10), rep(2, 10)))
    
getMoonPosition(data = data, 
  keep = c("altitude", "azimuth"))

Get Moon times

Description

Get Moon times

Usage

getMoonTimes(
  date = NULL,
  lat = NULL,
  lon = NULL,
  data = NULL,
  keep = c("rise", "set", "alwaysUp", "alwaysDown"),
  tz = "UTC",
  ...
)

Arguments

date

Date. Single or multiple Date. YYYY-MM-DD
lat

numeric. Single latitude
lon

numeric. Single longitude
data

data.frame. Alternative to use date, lat, lon for passing multiple coordinates
keep

character. Vector of variables to keep. See Details
tz

character. Timezone of results
...

Not used. (Maintenance only)

Details

Available variables are :

"rise"

Date. moonrise time

"set"

Date. moonset time

"alwaysUp"

Logical. TRUE if the moon never rises or sets and is always above the horizon during the day

"alwaysDown"

Logical. TRUE if the moon is always below the horizon

Value

data.frame

See Also

Other suncalc functions: getMoonIllumination(), getMoonPosition(), getSunlightPosition(), getSunlightTimes()

Examples

# one date
getMoonTimes(date = Sys.Date(), lat = 47.21, lon = -1.557, tz = "CET")

# multiple date + subset
getMoonTimes(date = seq.Date(Sys.Date()-9, Sys.Date(), by = 1), 
  keep = c("rise", "set", "alwaysUp"), 
  lat = 47.21, lon = -1.557, tz = "CET")
  
# multiple coordinates
data <- data.frame(date = seq.Date(Sys.Date()-9, Sys.Date(), by = 1), 
    lat = c(rep(50.1, 10), rep(49, 10)), 
    lon = c(rep(1.83, 10), rep(2, 10)))
    
getMoonTimes(data = data, tz = "CET")

Get Sunlight position

Description

Get Sunlight position

Usage

getSunlightPosition(
  date = NULL,
  lat = NULL,
  lon = NULL,
  data = NULL,
  keep = c("altitude", "azimuth")
)

Arguments

date

Single or multiple DateTime. Can be a Date (YYYY-MM-DD), a character in UTC (YYYY-MM-DD HH:mm:ss) or a POSIXct
lat

numeric. Single latitude
lon

numeric. Single longitude
data

data.frame. Alternative to use date, lat, lon for passing multiple coordinates
keep

character. Vector of variables to keep. See Details

Details

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

Value

data.frame

See Also

Other suncalc functions: getMoonIllumination(), getMoonPosition(), getMoonTimes(), getSunlightTimes()

Examples

# one date
getSunlightPosition(date = Sys.Date(), lat = 50.1, lon = 1.83)

# in character
getSunlightPosition(date = c("2017-05-12", "2017-05-12 00:00:00"), 
    lat = 50.1, lon = 1.83)

# in POSIXct
getSunlightPosition(date = as.POSIXct("2017-05-12 00:00:00", tz = "UTC"),
    lat = 50.1, lon = 1.83)
getSunlightPosition(date = as.POSIXct("2017-05-12 02:00:00", tz = "CET"),
    lat = 50.1, lon = 1.83)

# multiple date + subset
getSunlightPosition(date = seq.Date(Sys.Date()-9, Sys.Date(), by = 1), 
  keep = c("altitude"), 
  lat = 50.1, lon = 1.83)
  
# multiple coordinates
data <- data.frame(date = seq.Date(Sys.Date()-9, Sys.Date(), by = 1), 
    lat = c(rep(50.1, 10), rep(49, 10)), 
    lon = c(rep(1.83, 10), rep(2, 10)))
    
getSunlightPosition(data = data, 
  keep = c("altitude", "azimuth"))

Get Sunlight times

Description

Get Sunlight times

Usage

getSunlightTimes(
  date = NULL,
  lat = NULL,
  lon = NULL,
  data = NULL,
  keep = c("solarNoon", "nadir", "sunrise", "sunset", "sunriseEnd", "sunsetStart",
    "dawn", "dusk", "nauticalDawn", "nauticalDusk", "nightEnd", "night", "goldenHourEnd",
    "goldenHour"),
  tz = "UTC"
)

Arguments

date

Date. Single or multiple Date. YYYY-MM-DD
lat

numeric. Single latitude
lon

numeric. Single longitude
data

data.frame. Alternative to use date, lat, lon for passing multiple coordinates
keep

character. Vector of variables to keep. See Details
tz

character. Timezone of results

Details

Available variables are :

"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)

Value

data.frame

See Also

Other suncalc functions: getMoonIllumination(), getMoonPosition(), getMoonTimes(), getSunlightPosition()

Examples

# one date
getSunlightTimes(date = Sys.Date(), lat = 50.1, lon = 1.83, tz = "CET")

# multiple date + subset
getSunlightTimes(date = seq.Date(Sys.Date()-9, Sys.Date(), by = 1), 
  keep = c("sunrise", "sunriseEnd", "sunset", "sunsetStart"), 
  lat = 50.1, lon = 1.83, tz = "CET")
  
# multiple coordinates
data <- data.frame(date = seq.Date(Sys.Date()-9, Sys.Date(), by = 1), 
    lat = c(rep(50.1, 10), rep(49, 10)), 
    lon = c(rep(1.83, 10), rep(2, 10)))
    
getSunlightTimes(data = data, 
  keep = c("sunrise", "sunriseEnd", "sunset", "sunsetStart"), tz = "CET")