Meet Theo: I Just Needed a Theodolite

Skywarden gained support for detailed horizon profiles - but creating one required either expensive surveying hardware or apps that cost €20–30 for a task most astrophotographers do once or twice. So I built Theo: a free PWA that uses your phone's sensors and camera to capture azimuth/altitude pairs around the full 360° and export them as a .hrz file. This is the story of why it exists, how the…