To cite package ‘suntools’ in publications use:

Bivand R, Luque S (2026). suntools: Calculate Sun Position, Sunrise, Sunset, Solar Noon and Twilight. R package version 1.1.0.9000, https://github.com/adokter/suntools.

Corresponding BibTeX entry:

  @Manual{,
    title = {suntools: Calculate Sun Position, Sunrise, Sunset, Solar
      Noon and Twilight},
    author = {Roger Bivand and Sebastian Luque},
    year = {2026},
    note = {R package version 1.1.0.9000},
    url = {https://github.com/adokter/suntools},
  }