This wraps NREL's SOLPOS 2.0 and makes it accessible from postgres.
The SOLPOS code was vendored from: NREL/SolarPILOT which is licensed under a mixed MIT and GPLv3license.
Calculate the true solar time of a date and a location.
Required arguments
| Name | Type | Description |
|---|---|---|
ts |
TIMESTAMPTZ | the timestamp to be converted to solar time |
lat |
DOUBLE PRECISION | the latitude in decimal degrees of the position |
lon |
DOUBLE PRECISION | the longitude in decimal degrees of the position |
Optional arguments
| Name | Type | Description |
|---|---|---|
data_interval |
INT DEFAULT 0 | Interval of a measurement period in seconds. Forces solpos to use the time and date from the interval midpoint. The INPUT time is assumed to be the end of the measurement interval. |
Sample usage
Get the solar time for a date at a selected position:
SELECT solar_time('2023-10-06 15:30+00:00', 51.481, 7.217) solar_time
-----------------------
2023-10-06 16:10:43.7Get the solar time for a date at a selected position. Each timestamp is a one-hourly interval labelled at the end of the interval:
SELECT solar_time('2023-10-06 15:30+00:00', 51.481, 7.217, 3600) solar_time
-------------------------
2023-10-06 16:10:43.425SolarPILOT
Wagner, M.J. (2018). "SolarPILOT Open-Source Software Project: https://github.com/NREL/SolarPILOT/tree/21a1466398ec22db24a5a838e5133da58e347b83." Accessed (27/10/2022). National Renewable Energy Laboratory, Golden, Colorado.
Astronomical Solar Position
Michalsky, J. 1988. The Astronomical Almanac's algorithm for approximate solar position (1950-2050). Solar Energy 40 (3), 227-235.
Michalsky, J. 1988. ERRATA: The astronomical almanac's algorithm for approximate solar position (1950-2050). Solar Energy 41 (1), 113.
Distance from Sun to Earth
Spencer, J. W. 1971. Fourier series representation of the position of the sun. Search 2 (5), 172. NOTE: This paper gives solar position algorithms as well, but the Michalsky/Almanac algorithm above is more accurate.
Atmospheric Refraction Correction
Zimmerman, John C. 1981. Sun-pointing programs and their accuracy. SAND81-0761, Experimental Systems Operation Division 4721, Sandia National Laboratories, Albuquerque, NM.
Shadow Band Correction Factor
Drummond, A. J. 1956. A contribution to absolute pyrheliometry. Q. J. R. Meteorol.2 Soc. 82, 481-493.
Relative Optical Air Mass
Kasten, F. and Young, A. 1989. Revised optical air mass tables and approximation formula. Applied Optics 28 (22), 4735-4738.
Renormalization of KT (“PRIME”)
Perez, R., P. Ineichen, Seals, R., & Zelenka, A. 1990. Making full use of the clearness index for parameterizing hourly insolation conditions. Solar Energy 45 (2), 111-114.
Solar Position Relative to Earth
Iqbal, M. 1983. An Introduction to Solar Radiation. Academic Press, NY.