Horizon Alert

Horizon Alert tells you exactly when, where, and how to look up — and only when you can actually see something.

A "Tonight" feed gathers every event visible from your location into one chronological list: rocket launches, ISS passes, meteor showers, eclipses, spacewalks, and more. Each one shows a live countdown and which direction to face.

A "Nearby" map view centers on you with launch pads pinned on real satellite imagery and a visibility ring drawn at true geographic scale.

Real visibility intelligence: • Cloud cover at launch time, fetched per location • Sun elevation, so daylight launches aren't dressed up as visible • Distance from the pad, calculated as a great-circle bearing

Smart alerts you'll actually trust: • Choose your timings — 1 day, 12 hours, 2 hours, 30 minutes, 10 minutes, or T-zero • Notifications auto-cancel if conditions degrade • If the sky unexpectedly clears, you'll get a "conditions just cleared" alert

ISS overhead passes: • Rise compass, peak altitude, set compass, brightness • All predicted from your location, with countdowns

Built privacy-first: • No accounts, no analytics, no third-party tracking • Your location stays on your device • The only thing sent off your phone is a rounded latitude and longitude to fetch a cloud forecast for your general area

A clean, dark-mode-native experience for anyone who wants to look up.