NREL's Solar Position and Intensity (SOLPOS 2.0) C function (adopted in go lang) calculates the apparent solar position and intensity (theoretical maximum solar energy) based on date, time, and location on Earth for the years 1950–2050.
This packages requires Go 1.13. If you installed it and set up your GOPATH, just run:
go get -u github.com/maltegrosse/go-solpos
You can find some examples in the examples directory.
Please visit https://www.nrel.gov/grid/solar-resource/solpos.html for additional information.
Some additional helper functions have been added to the original application logic.
Note that your final decimal place values may vary based on your computer's floating-point storage and your compiler's mathematical algorithms. If you agree with NREL's values for at least 5 significant digits, assume it works.
If the difference is smaller than 0.000001,it is shown as 0.
| NREL | SOLPOS GO | Difference | |
|---|---|---|---|
| day | 22 | 22 | 0 |
| month | 7 | 7 | 0 |
| year | 1999 | 1999 | 0 |
| daynum | 203 | 203 | 0 |
| ampress | 1.326522 | 1.3265254683395031 | 0 |
| cosinc | 0.912569 | 0.9125697491698622 | 0 |
| prime | 1.037040 | 1.0370400228238181 | 0 |
| elevref | 48.409931 | 48.40974986370258 | 0.00018113629742089188 |
| etrtilt | 1207.547363 | 1207.5486465939166 | 0 |
| sbcf | 1.201910 | 1.2019108852729568 | 0 |
| sunrise | 347.173431 | 347.1746053157332 | 0 |
| sunset | 1181.111206 | 1181.1101930505447 | 0.0010129494553439145 |
| unprime | 0.964283 | 0.9642829379690094 | 0 |
| zenref | 41.590069 | 41.59025013629742 | 0 |
| amass | 1.335752 | 1.3357557648388834 | 0 |
| azim | 97.032875 | 97.03331438627943 | 0 |
| etr | 989.668518 | 989.6657077767151 | 0.0028102232848823405 |
| etrn | 1323.239868 | 1323.2398374944908 | 3.0505509130307473e-05 |
Adoption in Golang under MIT license 2020 © Malte Grosse.