Generates and Samples Realistic Terrestrial Atmospheres // Generates physically based sky environment maps and radiance samples using the spectral Hosek-Wilkie and Prague atmosphere models. Functions write high-dynamic-range 'OpenEXR' domes in latitude-longitude projections, compute per-direction RGB or 55-channel values, and optionally composite time-accurate star fields and moon phases. Features include automatic sun and moon positioning from date, time and location, support for sea-level and high-altitude observers, wide-spectrum coefficients, and multithreaded C++ acceleration for fast, high-resolution output. For model details, see Hosek and Wilkie (2012) doi:10.1145/2185520.2185591, Hosek and Wilkie (2013) doi:10.1109/MCG.2013.18, Wilkie et al. (2021) doi:10.1145/3450626.3459758, and Vevoda et al. (2022) doi:10.1111/cgf.14677.