Satellite SentinelISS & Starlink tracker

Satellite Sentinel calls you outside for passes you can see with your own eyes, without a telescope or binoculars. On a good pass the Space Station is brighter than any star in the sky, easily visible from light-polluted suburbs, and binoculars only make it a slightly bigger bright dot. The hard part was never the seeing; it was knowing the minute and the direction.

Satellite Sentinel’s pass list comes in streaks because visibility itself does. A pass is only visible when your sky is dark and the Station is still catching sunlight, and those two conditions overlap only in the hour or two around dawn and dusk. During a favorable stretch you might get visible passes several evenings in a row; then the orbit’s geometry drifts and you get nothing for days or weeks. That is orbital mechanics, not a fault.

Satellite Sentinel downloads a fresh set of orbital elements every day and then runs SGP4 propagation on the device itself (the same math used to track objects in Earth orbit) rather than reading answers out of a lookup table. It predicts passes up to 24 hours ahead for your exact location and rates each one, so you know whether tonight’s is worth stepping outside for.

Yes, for a US ZIP code. Satellite Sentinel asks for your ZIP code during setup and then predicts visible ISS passes for that location up to 24 hours ahead, with a countdown, a compass direction such as LOOK NORTHWEST, and a quality rating for each pass. It works in the United States only, and it lists the next 24 hours, not a calendar of the coming weeks.

Satellite Sentinel tracks the International Space Station and up to 100 Starlink satellites, and shows pass countdowns for the ISS and Starlink. It is not a pass predictor for every satellite in orbit.

PlankLabs gadgets join a 2.4 GHz WiFi network. They don’t speak 5 GHz-only WiFi. That is the radio in the silicon rather than a software choice, and it comes with a consolation prize: 2.4 GHz travels farther and through walls better than 5 GHz, which suits a gadget that lives wherever it looks best rather than next to the router.

PlankLabs gadgets update themselves automatically, over the air. When improvements, fixes, or new features ship, your gadget quietly downloads them on its own. You don’t have to plug in a cable, download a file, or click anything.