Credits & data sources
What the planner is built on, and who to thank. Last updated 22 September 2026.
Maps and elevation
| OpenStreetMap | Map data © OpenStreetMap contributors, ODbL. The Planner and Streets basemaps are OpenStreetMap data rendered by OpenFreeMap (Positron and Liberty styles). |
| MapTiler | Satellite, hybrid and outdoor maps, place search, and the terrain fallback. © MapTiler © OpenStreetMap contributors. |
| AWS Terrain Tiles | Elevation for horizons, sightlines, shadows, slope, hillshade and 3D. Mapzen terrain tiles on the AWS Open Data registry; underlying DEMs from USGS 3DEP, SRTM (NASA/USGS), GMTED2010, ETOPO1 (NOAA), Natural Resources Canada, INEGI, Geoscience Australia, LINZ, Kartverket, data.gov.uk, and others as listed on the registry page. |
| Mapillary | Street-level photos © Mapillary contributors, CC BY-SA 4.0, shown with a link to the original. |
| MapLibre GL JS | The map renderer (BSD-3-Clause). PMTiles reader (BSD-3-Clause) for the forecast tiles. |
Weather, climate, water and snow
| Open-Meteo | Point forecast, eight-model agreement (ECMWF IFS, NOAA GFS/HRRR, DWD ICON, Environment Canada GEM, UK Met Office, JMA, Météo-France ARPEGE/AROME, and Open-Meteo's best match), ERA5 climatology and light-quality overlays. Weather data by Open-Meteo.com, CC BY 4.0. Air transparency from Copernicus Atmosphere Monitoring Service (CAMS) via Open-Meteo. |
| NOAA CO-OPS | Tide predictions for US stations (public domain). |
| USGS | River stage and discharge, provisional data (public domain). |
| USDA NRCS SNOTEL | Snowpack (public domain). |
| NOAA SWPC | Space weather: solar wind, OVATION aurora, Kp, 27-day outlook (public domain). |
| NASA GIBS | Black Marble night-lights imagery (public domain), the sky-glow proxy. |
| Skyfire | The sunset- and sunrise-colour forecast, computed with the Skyfire method under agreement with Skyfire Services on NOAA HRRR model data (public domain). |
The sky
| Sun, Moon, planets | Positions after Jean Meeus, Astronomical Algorithms (2nd ed.): VSOP87 for the Sun and planets, ELP-2000/82 for the Moon, with nutation, ΔT, refraction and topocentric parallax; checked against JPL Horizons. Planet magnitudes from the Astronomical Almanac. |
| Stars | Yale Bright Star Catalogue, 5th revised edition (Hoffleit & Warren 1991), public domain. Proper names from the IAU Working Group on Star Names. |
| Constellations | Constellation figures: IAU and Sky & Telescope magazine (Roger Sinnott & Rick Fienberg), via d3-celestial (Olaf Frohn, BSD-3). |
| Milky Way | Milky Way outlines: José R. Vieira, via d3-celestial. |
| Deep sky | Messier objects from the SEDS Messier database (Hartmut Frommert) via d3-celestial. |
| Satellites | Orbital elements: CelesTrak. Propagation with satellite.js (MIT). |
| Comets | Comet elements: IAU Minor Planet Center. |
| Eclipses | Computed from the same ephemeris; exposure arithmetic after Fred Espenak's published tables. |
| Magnetic declination | NOAA / NCEI and the British Geological Survey, World Magnetic Model 2025 (public domain). |
| Time zones | Zone lookup by tz-lookup (MIT); rules from the IANA time-zone database via the browser. |
Infrastructure
Cloudflare Pages hosts the site and its API; Supabase holds accounts and synced data; PostHog counts anonymous feature use; payments by Lemon Squeezy, Apple and Google. Built with Vite.
Trademarks
"The Photographer's Ephemeris" and "TPE" are trademarks of their owner; this product is not affiliated with them. Skyfire is a trademark of Skyfire Services, used under agreement. All other names belong to their owners.