init

README.md

@@ -1,3 +1,44 @@
-# azimut
+# Sun's azimuth calc
 
-Расчет высоты и азимута Солнца над горизонтом
+The height of the Sun (altitude) is the arc of a vertical circle from the mathematical horizon to the central point of the solar disk (the angle between the plane of the mathematical horizon and the direction to the center of the Sun). The height is calculated from 0 ° to 90 °.
+
+The azimuth of the Sun (azimut) is an arc in the plane of the mathematical horizon from the point of the north to the vertical circle of the Sun. Azimuth is calculated in the direction of the daily rotation of the celestial sphere, i.e. clockwise in the northern hemisphere and counterclockwise in the southern hemisphere, from the point of the north in the range from 0 ° to 360 °.
+
+## Using
+
+Get the sun azimuth [deg] and altitude above the horizon [deg]:
+
+```
+local azimut = require('azimut')
+
+date = '2025-01-03 14:55:55' -- UTC time or datetime with offset
+
+azumut, altitude = azimut.get(date,54.5,54.2)
+
+```
+Get the full data:
+
+```
+local azimut = require('azimut')
+
+date = '2025-01-03 14:55:55' -- UTC time or datetime with offset
+
+data = azimut.data(date,54.5,54.2)
+
+```
+
+Where:
+
+- azimut - Sun azimuth [deg]
+- altitude - Sun's altitude above the horizon [deg]
+- perihelion_lon - Longitude of perihelion
+- eccentricity - Orbital eccentricity		
+- anomaly - Average anomaly
+- ecliptic_angle - Obliquity of the ecliptic plane
+- eccentric - Eccentric anomaly
+- ecliptic_lon - Sun's Ecliptic longitude
+- ascension - Equatorial coordinates of the Sun: right ascension
+- declination - Equatorial coordinates of the Sun: declination
+- sidereal_time_utc - Greenwich's sidereal time
+- sidereal_time_local - Point sidereal time
+- hour_angle - Sun hour angle

azimut.lua

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+local date = require("date")
+
+local _M = {}
+
+local azimut,altitude,w,e,m,ecliptic,Ee,longt,RA,DEC,GMST0,SIDTIME,HA
+
+local rad = math.rad
+local deg = math.deg
+local floor = math.floor
+local cir = function(x) return x - math.floor (x / 360.0) * 360.0 end
+local cos = function(d) return math.cos(rad(d)) end
+local acos = function(d) return deg(math.acos(d)) end
+local sin = function(d) return math.sin(rad(d)) end
+local asin = function(d) return deg(math.asin(d)) end
+local tan = function(d) return math.tan(rad(d)) end
+local atan = function(d) return deg(math.atan(rad(d))) end
+local atan2 = function(x,y) return deg(math.atan2(rad(x),rad(y))) end
+
+local function days(utc)
+	utc = date(utc) or date():toutc()
+	local d = date.diff(utc, date(2000, 1, 1))
+	local UT = utc:gethours()+(utc:getminutes()/60)
+	return floor(d:spandays())+UT/24,UT
+end
+
+local function solar(utc,lat,lon)
+	local days,UT = days(utc)
+	w = 282.9404 + 0.0000470935*days    -- долгота перигелия
+	e = 0.016709-0.000000001151*days     --эксцентриситет орбиты
+	m = cir(356.0470 + 0.9856002585*days)    --средняя аномалия
+	ecliptic = 23.4393-0.0000003563*days -- наклон плоскости эклиптики	
+	Ee = m+e*sin(m)*(1+e*cos(m)) --эксцентрическая аномалия	
+	local L = cir(w+m) 
+	local x = cos(Ee)-e
+	local y = sin(Ee)*math.sqrt(1-e*e)
+	local r = math.sqrt(x*x+y*y)
+	local v = atan2(y,x)
+	longt = cir(v+w) --эклиптическая долгота Солнца 
+	local x = r*cos(longt)
+	local y = r*sin(longt)
+	local z = 0 
+	local xequat = x
+	local yequat = y*cos(ecliptic)-z*sin(ecliptic)
+	local zequat = y*sin(ecliptic)+z*cos(ecliptic)
+	-- экваториальные координаты Солнца
+	RA  = atan2(yequat,xequat)-- прямое восхождение
+	DEC = asin(zequat/r) -- склонение
+	--расчет азимутальных координат 
+	GMST0=L/15.0+12.0 -- звездное время для гринвичского меридиана 
+	SIDTIME = GMST0+UT+lon/15.0   -- Звездное время
+	if SIDTIME<0 then SIDTIME = SIDTIME+24.0 end
+	if SIDTIME>24 then SIDTIME = SIDTIME-24.0 end
+	HA = SIDTIME*15.0-RA --Часовой угол
+	local xx = cos(HA)*cos(DEC)
+	local yy = sin(HA)*cos(DEC)
+	local zz = sin(DEC)
+	local Xhor = xx*sin(lat)-zz*cos(lat)
+	local Yhor=yy;
+	local Zhor=xx*cos(lat)+zz*sin(lat)
+	azimut = atan2(Yhor,Xhor)+180 -- азимут Солнца [град]
+	altitude = asin(Zhor) -- высота Солнца над горизонтом [град]
+end
+
+function _M.get(utc,lat,lon)
+	solar(utc,lat,lon)
+	return azimut,altitude
+end
+
+function _M.data(utc,lat,lon)
+	solar(utc,lat,lon)
+	return {
+		['azimut'] = azimut, -- Sun azimuth [deg]
+		['altitude'] = altitude,-- Sun's altitude above the horizon [deg]
+		['perihelion_lon'] = w, -- Longitude of perihelion
+		['eccentricity'] = e, -- Orbital eccentricity		
+		['anomaly'] = m, -- Average anomaly
+		['ecliptic_angle'] = ecliptic, -- Obliquity of the ecliptic plane
+		['eccentric'] = Ee, -- Eccentric anomaly
+		['ecliptic_lon'] = longt, -- Sun's Ecliptic longitude
+		['ascension'] = RA, -- Equatorial coordinates of the Sun: right ascension
+		['declination'] = DEC,  -- Equatorial coordinates of the Sun: declination
+		['sidereal_time_utc'] = GMST0, -- Greenwich's sidereal time
+		['sidereal_time_local'] = SIDTIME, -- Point sidereal time
+		['hour_angle'] = HA -- Sun hour angle
+	}
+end
+
+return _M
+
+

test.lua

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+local azimut = require('azimut')
+
+print(azimut.get('2025-05-27 09:11:14+04',54.314192, 48.403132))
+