Heavens-Above Pro vs B4UFLY by FAA Usage & Stats

When can I see the ISS? What's that light in the sky? The official Heavens-Above app provides you with precise pass predictions for the ISS, visible satellites and radio satellites. Main features include: Live sky chart See what's in the sky above you right now or at a given moment. Pass predictions Get precise predictions for passes of the International Space Station (ISS) and most visible satellites. Radio satellites Get passes for amateur radio satellites, complete with uplink and downlink information. Comets Find the location of bright comets, including NEOWISE, in the sky. All calculations performed locally Predictions are generated right on your phone so you only need a data connection every few days. Orbit and ground track See details about the orbit of any selected satellite rendered and with all relevant data. Pro version only: The position of all satellites can be displayed at once and filtered down. Satellite details Get detailed information about any satellite, as provided by our Heavens-Above website. Timeline Get a visual overview over passes and animate the position of satellites on the sky chart and on the ground track. Pro version only: The timeline contains the elevation and detailed brightness prediction of passes. Night mode An optional red on black color scheme to preserve your night vision. Tracker Easily find or identify any object in the sky by orienting your device towards it. Calendar Integration Quickly add interesting passes to your calendar so you won't miss them. Custom TLEs Pro version only: You can create satellite entries with your own TLEs. No advertisements Pro version only: This version is free of advertisements. You can try the free version before buying this one.