SolarPosition.jl

SolarPosition.jl provides a simple, unified interface to a collection of validated solar position algorithms written in pure, performant julia.

Solar positioning algorithms are commonly used to calculate the solar zenith and azimuth angles, which are essential for various applications where the sun is important, such as:

• Solar energy systems
• Building design
• Climate studies
• Astronomy

Acknowledgement

This package is based on the work done by researchers in the field of solar photovoltaics in the packages solposx and pvlib-python. In particular the positioning and refraction methods have been adapted from solposx, while the SPA algorithm and the deltat calculation are ported from pvlib-python. These packages also provide validation data necessary to ensure correctness of the algorithm implementations.

Example Usage

julia> using SolarPosition, Dates

# define observer location (latitude, longitude, altitude in meters)
julia> obs = Observer(52.35888, 4.88185, 100.0)  # Van Gogh Museum, Amsterdam
Observer(latitude=52.35888°, longitude=4.88185°, altitude=100.0m)

# a few hours of timestamps
julia> times = collect(DateTime(2023, 6, 21, 10):Hour(1):DateTime(2023, 6, 21, 15));

# compute solar positions for all timestamps
julia> positions = solar_position(obs, times)
6-element StructArray(::Vector{Float64}, ::Vector{Float64}, ::Vector{Float64}) with eltype SolPos{Float64}:
 SolPos(azimuth=136.1908215897601°, elevation=55.13208390809107°, zenith=34.86791609190893°)
 SolPos(azimuth=160.3753655770986°, elevation=59.974081481305134°, zenith=30.025918518694862°)
 SolPos(azimuth=188.3992597996431°, elevation=60.87918930278924°, zenith=29.120810697210757°)
 SolPos(azimuth=214.62987222053295°, elevation=57.493462259959394°, zenith=32.5065377400406°)
 SolPos(azimuth=235.5258846451899°, elevation=50.992647293443966°, zenith=39.007352706556034°)
 SolPos(azimuth=251.77304757136397°, elevation=42.790197455865076°, zenith=47.209802544134924°)

Solar positioning algorithms

Here we provide an overview of the solar positioning algorithms currently implemented in SolarPosition.jl. Each algorithm is described with its reference paper, claimed accuracy and implementation status.

Algorithm	Reference	Accuracy	Default Refraction	Status
PSA	Blanco-Muriel et al.	±0.0083°	None	✅
NOAA	Global Monitoring Laboratory	±0.0167°	HUGHES	✅
Walraven	Walraven, 1978	±0.0100°	None	✅
USNO	U.S. Naval Observatory	±0.0500°	None	✅
SPA	Reda & Andreas, 2004	±0.0003°	Built-in	✅

Refraction correction algorithms

Atmospheric refraction correction algorithms available in SolarPosition.jl.

Algorithm	Reference	Atmospheric Parameters	Status
HUGHES	Hughes, 1985	Pressure, Temperature	✅
ARCHER	Archer et al., 1980	None	✅
BENNETT	Bennett, 1982	Pressure, Temperature	✅
MICHALSKY	Michalsky, 1988	None	✅
SG2	Blanc & Wald, 2012	Pressure, Temperature	✅
SPA	Reda & Andreas, 2004	Pressure, Temperature	✅

How to Cite

If you use SolarPosition.jl in your work, please cite using the reference given in CITATION.cff.

Contributing

If you want to make contributions of any kind, please first that a look into our contributing guide directly on GitHub or the contributing page on the website