Space & Astronomy Toolkit

Free utilities for satellite tracking, pass prediction, and space observation.

Night Sky Planner

Plan your stargazing session tonight. Get astronomical twilight times, dark sky window, golden hour, moon phase with illumination, visible satellite passes, and a stargazing quality rating for your ZIP code.

Open Planner

ISS Tracker

Monitor the International Space Station in real-time. View current latitude, longitude, altitude, velocity, and regional position. Project upcoming pass times over your location.

Open Tracker

Satellite Pass Predictor

Predict upcoming visible passes for amateur radio satellites, weather satellites, science missions, and space stations. See rise, culmination, and set times in your local timezone.

Open Predictor

Lunar Phase Calendar

Monthly moon phase calendar with illumination percentages, rise/set times by ZIP code, and countdowns to the next New Moon, First Quarter, Full Moon, and Last Quarter. Powered by Skyfield — no external APIs.

Open Calendar