Data
- Place names: GeoNames, © GeoNames contributors, licensed under CC BY 4.0. We normalise names for searching and make no other change.
- Time zone boundaries: © OpenStreetMap contributors, through timezone-boundary-builder and the timezonefinder data package, licensed under the Open Database License 1.0. Used unmodified.
- Clock rules: the IANA Time Zone Database, in the public domain.
Calculation code
- Astronomy Engine, © Don Cross, MIT License.
- timezonefinder, © Jannik Kissinger, MIT License.
- NumPy and pycparser, BSD 3-Clause License.
- cffi, MIT No Attribution License.
- FlatBuffers, Apache License 2.0.
Site code
- Astro and Tailwind CSS, MIT License.
- FastAPI and SlowAPI, MIT License.
- Uvicorn, BSD 3-Clause License.
Fonts and icons
- Fraunces, © The Fraunces Project Authors, SIL Open Font License 1.1.
- Source Serif 4, © Adobe, SIL Open Font License 1.1.
- Tabler Icons, © Paweł Kuna, MIT License.
Reference data for our checks
We compare our results with JPL Horizons from NASA’s Jet Propulsion Laboratory, and with the Swiss Ephemeris from Astrodienst. Neither runs on this site, and neither has reviewed or endorsed it. How we calculate has the details.
Drawings
Astro, the mouse and the rooms of the parlor were made for this site. They aren’t stock images.
Last updated October 30, 2026.