https://observablehq.com/@ambassadors/your-sunset-their-sunrise
Every day, somewhere on Earth, your sunrise is someone else’s sunset. This notebook finds those two points for you: given your location, it draws two spots on your same latitude line — one to the west having its sunrise the moment you have your sunset, one to the east having its sunset the moment you have your sunrise.
It’s built as a flat Mercator map showing your pin and both paired points at once, with an option to switch to a rotatable 3D globe. Under the hood it’s pure spherical geometry — latitude and today’s solar declination — cross-checked live against an independent astronomical library so the math validates itself as you move around.
Big thanks to @neocarto for Geoviz, which powers the map rendering here. Along the way I dug into its data-driven tooltip and symbol APIs to get proper hover tooltips and a custom pin marker working on the maps. Observable AI was also a big help in prototyping and debugging:
