MIDC SPA Calculator
Compute the solar position from universal time
and location using NREL's
Solar Position Algorithm (SPA)
.
Required input values:
Start Date
January
February
March
April
May
June
July
August
September
October
November
December
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End Date
January
February
March
April
May
June
July
August
September
October
November
December
1
2
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5
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9
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Output Interval
1
2
5
10
15
30
60
Second
Minute
Observer latitude (negative south of equator) [degrees]
Observer longitude (negative west of Greenwich) [degrees]
Observer time zone (negative west of Greenwich) [degrees]
Observer elevation [meters]
Annual average local pressure [millibars]
Annual average local temperature [degrees Celsius]
ΔT
= Terrestrial Time (TT) - Universal Time (UT) [seconds]
Optional input values:
Surface azimuth rotation (measured from south to projection
of surface normal on horizontal plane, negative west) [degrees]
Surface slope (measured from the horizontal plane) [degrees]
Atmospheric refraction at sunrise and sunset [degrees]
Check desired final output values:
Topocentric zenith angle [degrees]
Topocentric azimuth angle (eastward from north) [ 0 to 360 degrees]
Topocentric azimuth angle (westward from south) [-180 to 180 degrees]
Surface incidence angle [degrees]
Local sunrise time (+/- 30 seconds) [fractional hour]
Local sun transit time (or solar noon) [fractional hour]
Local sunset time (+/- 30 seconds) [fractional hour]
Check desired intermediate output values:
Julian day
Julian century
Julian ephemeris day
Julian ephemeris century
Julian ephemeris millennium
Earth heliocentric longitude [degrees]
Earth heliocentric latitude [degrees]
Earth radius vector [Astronomical Units, AU]
Geocentric longitude [degrees]
Geocentric latitude [degrees]
Mean elongation (moon-sun) [degrees]
Mean anomaly (sun) [degrees]
Mean anomaly (moon) [degrees]
Argument latitude (moon) [degrees]
Ascending longitude (moon) [degrees]
Nutation longitude [degrees]
Nutation obliquity [degrees]
Ecliptic mean obliquity [arc seconds]
Ecliptic true obliquity [degrees]
Aberration correction [degrees]
Apparent sun longitude [degrees]
Greenwich mean sidereal time [degrees]
Greenwich sidereal time [degrees]
Geocentric sun right ascension [degrees]
Geocentric sun declination [degrees]
Observer hour angle [degrees]
Sun equatorial horizontal parallax [degrees]
Sun right ascension parallax [degrees]
Topocentric sun declination [degrees]
Topocentric sun right ascension [degrees]
Topocentric local hour angle [degrees]
Topocentric elevation angle (uncorrected) [degrees]
Atmospheric refraction correction [degrees]
Topocentric elevation angle (corrected) [degrees]
Equation of time [minutes]
Sunrise hour angle [degrees]
Sunset hour angle [degrees]
Sun transit altitude [degrees]
ASCII Text
ZIP Compressed
Please read the
disclaimer
and
copyright notice
before using this product.
The RReD
C
has more information about
SPA and the C source code
.
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