Carlos Adrian Correa Florez, MINES ParisTech PhD, PERSEE center




CoRDÉES : gouvernance énergétique de quartier


Prédiction solaire pour des suiveurs photovoltaïques


The REstable project



Retrouvez nos coordonnées
sur la page
Informations pratiques

Solar Geometry

These libraries in C and Python provide means to compute the position of the Sun and related astronomical quantities

Back to Software



Two libraries are available: "solar geometry" and the more recent and accurate "solar geometry 2". They comprises the following items:

  • geometry of the solar beam,
  • position of the sun in the sky,
  • and for "solar geometry" only, sunrise, sunset and astronomical daylength, changing the time system,  the extraterrestrial irradiation, and procedures providing the above parameters for a given day, or on monthly or yearly averages.

The libraries account for the differences between geographic and geocentric coordinates. This difference is only for latitude and reaches its maximum of 0.2 degree (approx. 20 km) at 45 degrees. Coordinates in equations for sun geometry are geocentric, while latitudes used by customers are geographic.

These software codes are available under a Creative Commons license (CC-BY).  CC-by icon

Solar Geometry

Solar Geometry is the first generation of library for computing the relative position of the sun and the earth. It has been used to develop many tools relating to the method Heliosat-2. Formulas are from the European Solar Radiation Atlas of the European Commission. Download solar geometry in C. For the compilation, refer to the files README and INSTALL. There is no example of use of the library, but the codes provide a satisfying number of comments to help using this library.

Solar Geometry 2

Solar Geometry 2 (SG2) is the second generation of library for computing the relative position of the sun and the earth. Valid over the time period 1980-2100, the algorithm is 20 times faster than the well-know SPA algorithm, with an accuracy order of approx. 0.005°. Reference article: Blanc P. and L. Wald,  The SG2 algorithm for a fast and accurate computation of the position of the sun for multi-decadal time period. Solar Energy 88, 3072-3083, 2012, doi: 10.1016/j.solener.2012.07.018.

  • The code is available at github (https://github.com/gschwind/sg2).
  • The code is also available in Python available via pip.
  • A Web processing Service is also available. It executes Solar Geometry 2 with geographical coordinates and time period as inputs and returns topocentric declination and hour angle, topocentric Sun azimuth angle and elevation angle without refraction correction.

Back to Software

Softwares : Solar geometry, position of the Sun - Mines Paris - PSL


Femmes de science

Formation Femmes de science Chercheuses confirmées, doctorantes, élèves ou alumni,…
> En savoir +

Visite de MINES Paris par les petits débrouillards

Recherche Visite de MINES Paris par les petits débrouillards Les adolescents de Vallauris découvrent…
> En savoir +

A la découverte des paléoclimats

Formation A la découverte des paléoclimats Jean Robert Petit revient sur l'histoire de…
> En savoir +

Agir contre les violences sexistes et sexuelles

Formation Agir contre les violences sexistes et sexuelles Les violences sexistes et sexuelles, le…
> En savoir +

Le Rapport d'activité 2020 est en ligne

Formation Le Rapport d'activité 2020 est en ligne Image de couverture du RA 2020, inspirée par des recherches du…
> En savoir +

Pourquoi éclipser le solaire ?

Formation Pourquoi éclipser le solaire ? Philippe Blanc : « rétablir certaines vérités sur le…
> En savoir +

+ Toutes les actualités

Mentions légales efil.fr © 2014 Mines Paris - PSL