Data & credits

LumenScout is built on open data and open-source software. Thank you to everyone below.

Weather forecasts: Weather data by Open-Meteo.com, licensed CC BY 4.0 (terms). Open-Meteo combines national weather services' models, including NOAA, DWD and Météo-France.
Terrain horizon: elevations from the Open-Meteo Elevation API, based on the Copernicus DEM GLO-90. Produced using products © DLR e.V. (2014-2018) and © Airbus Defence and Space GmbH (2021) provided under COPERNICUS by the European Union and ESA; all rights reserved.
Sky darkness: VIIRS Annual Nighttime Lights (VNL V2.2), 2025, Earth Observation Group, Payne Institute for Public Policy, Colorado School of Mines, licensed CC BY 4.0. Elvidge, C.D., Zhizhin, M., Ghosh, T., Hsu, F.C. and Taneja, J. (2021), "Annual time series of global VIIRS nighttime lights derived from monthly averages: 2012 to 2019", Remote Sensing 13(5), 922, doi:10.3390/rs13050922. LumenScout shrinks it to a 0.1° grid, spreads each town's glow over the surrounding 200 km and converts it to an estimated Bortle class; the estimates are LumenScout's, not EOG's.
Smoke and haze: aerosol optical depth from the Open-Meteo Air Quality API, based on the Copernicus Atmosphere Monitoring Service (CAMS). Generated using Copernicus Atmosphere Monitoring Service information 2026; neither the European Commission nor ECMWF is responsible for any use made of it.
Place search: the Open-Meteo Geocoding API, with place data from GeoNames (CC BY 4.0).
Place names for your location: BigDataCloud free reverse geocoding API.

Sky glow falling off with distance^-2.5: Walker, M.F. (1977), "The effects of urban lighting on the brightness of the night sky", Publications of the Astronomical Society of the Pacific 89, 405-409, doi:10.1086/130142.
Bortle Dark-Sky Scale: Bortle, J.E. (2001), "Introducing the Bortle Dark-Sky Scale", Sky & Telescope, February 2001.