Module suntime
-- Author: Martin Zwicknagl (zwim) -- Date: 2021-10-29 -- The current source code of this file can be found on https://github.com/zwim/suntime.
Module to calculate ephemeris and other times depending on the sun position.
Maximal errors from 2020-2050 (compared to https://midcdmz.nrel.gov/spa/) are:
- -43.52° Christchurch 66s
- -20.16° Mauritius: 25s
- 20.30° Honolulu: 47s
- 33.58° Casablanca: 24s
- 35.68° Tokio: 50s
- 37.97° Athene: 24s
- 38° Sacramento: 67s
- 41.91° Rome: 27s
- 47.25° Innsbruck: 13s
- 52.32° Berlin: 30s
- 59.92° Oslo: 42s
- 64.14° Reykjavik: 69s
- 65.69° Akureyri: <24s (except *)
- 70.67° Hammerfest: <105s (except **)
*) A few days around beginning of summer (error <290s)
**) A few days after and before midnight sun (error <1200s)
Usage:
local SunTime = require("suntime")
time_zone = 0
altitude = 50
degree = true
SunTime:setPosition("Reykjavik", 64.14381, -21.92626, timezone, altitude, degree)
SunTime:setAdvanced()
SunTime:setDate()
SunTime:calculateTimes()
print(SunTime.rise, SunTime.set, SunTime.set_civil) -- or similar see calculateTime()
Functions
| SunTime:setPosition (name, latitude, longitude, time_zone, altitude, degree) | Set position for later calculations |
| SunTime:setSimple () | Use a simple equation of time (valid for the years 2008-2027) |
| SunTime:setAdvanced () | Use an advanced equation of time (valid for the years 1800-2200 at least) |
| SunTime:calculateTimes (fast_twilight) | Calculates the ephemeris and twilight times |
Fields
| SunTime.getZgl | Function to get the equation of time, can be set by setSimple() or setAdvanced() |
Functions
- SunTime:setPosition (name, latitude, longitude, time_zone, altitude, degree)
-
Set position for later calculations
Parameters:
- name Name of the location
- latitude Geographical latitude, North is positive
- longitude Geographical longitude, West is negative
- time_zone Timezone e.g. CET = +1; if nil try to autodetect the current zone
- altitude Altitude of the location above the sea level
- degree
if
nillatitude and longitude are in radian, else in decimal degree
- SunTime:setSimple ()
- Use a simple equation of time (valid for the years 2008-2027)
- SunTime:setAdvanced ()
- Use an advanced equation of time (valid for the years 1800-2200 at least)
- SunTime:calculateTimes (fast_twilight)
-
Calculates the ephemeris and twilight times
Parameters:
- fast_twilight If not nil, then exact twilight times will be calculated.
Usage:
SunTime:calculateTimes(fast_twilight) Times are in hours or
nilif not applicable. You can then access: self.midnight_beginning self.rise_astronomic self.rise_nautic self.rise_civil self.rise self.noon self.set self.set_civil self.set_nautic self.set_astronomic self.midnight Or as values in a table: self.times[1] midnight_beginning self.times[2] rise_astronomic self.times[3] rise_nautic self.times[4] rise_civil self.times[5] rise self.times[6] noon self.times[7] set self.times[8] set_civil self.times[9] set_nautic self.times[10] set_astronomic self.times[11] midnight