Calculation of sunrise and sunset: Difference between revisions
From WickyWiki
mNo edit summary |
mNo edit summary |
||
| Line 22: | Line 22: | ||
vDecl = 0.006918 - 0.399912 * COS(vY) + 0.070257 * SIN(vY) - 0.006758 * COS(2 * vY) + 0.000907 * SIN(2 * vY) - 0.002697 * COS(3 * vY) + 0.00148 * SIN (3 * vY) | vDecl = 0.006918 - 0.399912 * COS(vY) + 0.070257 * SIN(vY) - 0.006758 * COS(2 * vY) + 0.000907 * SIN(2 * vY) - 0.002697 * COS(3 * vY) + 0.00148 * SIN (3 * vY) | ||
For sunrise or sunset, the zenith is set to 90.833 degrees (the approximate correction for atmospheric refraction at sunrise and sunset, and the size of the solar disk). Hours angle: | For sunrise or sunset, the zenith is set to 90.833 degrees (the approximate correction for atmospheric refraction at sunrise and sunset, and the size of the solar disk). Hours angle (radians): | ||
vHa = ACOS( COS( | vHa = ACOS( COS( TO_RADIANS(90.833) ) / COS(vLat) * COS(vDecl) - TAN(vLat) * TAN(vDecl) ) | ||
Sunrise UTC minutes | Sunrise UTC minutes | ||
vUtcMinsSunrise = 360 * 2 - 4 * (vLon + vHa) - vEqtime | vUtcMinsSunrise = 360 * 2 - 4 * (vLon + TO_DEGREES(vHa) ) - vEqtime | ||
Noon UTC minutes | Noon UTC minutes | ||
| Line 36: | Line 36: | ||
Sunset UTC minutes | Sunset UTC minutes | ||
vUtcMinsSunset = 360 * 2 - 4 * (vLon - vHa) - vEqtime | vUtcMinsSunset = 360 * 2 - 4 * (vLon - TO_DEGREES(vHa) ) - vEqtime | ||
Sunset local time in fractional day. For Europe/Amsterdam --> vTimezone=+1 or +2 (DST) | |||
( | (vUtcMinsSunset / 60 + vTimezone) / 24 | ||
Revision as of 12:37, 3 March 2019
Source:
- https://www.esrl.noaa.gov/gmd/grad/solcalc/
- https://www.esrl.noaa.gov/gmd/grad/solcalc/solareqns.PDF
Input example:
- Date --> vDayOfYear
- Date --> vLeapyear
Fractional year (radians)
vY = 2 * PI() / (365 + vLeapYear) * (vDayOfYear - 1 )
Equation of time (minutes)
vEqtime = 229.18 * (0.000075 + 0.001868 * COS( vY ) - 0.032077 * SIN( vY ) - 0.014615 * COS(2 * vY ) - 0.040849 * SIN(2 * vY )
Solar declination angle (radians).
vDecl = 0.006918 - 0.399912 * COS(vY) + 0.070257 * SIN(vY) - 0.006758 * COS(2 * vY) + 0.000907 * SIN(2 * vY) - 0.002697 * COS(3 * vY) + 0.00148 * SIN (3 * vY)
For sunrise or sunset, the zenith is set to 90.833 degrees (the approximate correction for atmospheric refraction at sunrise and sunset, and the size of the solar disk). Hours angle (radians):
vHa = ACOS( COS( TO_RADIANS(90.833) ) / COS(vLat) * COS(vDecl) - TAN(vLat) * TAN(vDecl) )
Sunrise UTC minutes
vUtcMinsSunrise = 360 * 2 - 4 * (vLon + TO_DEGREES(vHa) ) - vEqtime
Noon UTC minutes
vUtcMinsNoon = 360 * 2 - 4 * vLon - vEqtime
Sunset UTC minutes
vUtcMinsSunset = 360 * 2 - 4 * (vLon - TO_DEGREES(vHa) ) - vEqtime
Sunset local time in fractional day. For Europe/Amsterdam --> vTimezone=+1 or +2 (DST)
(vUtcMinsSunset / 60 + vTimezone) / 24
