Important

Visual observing of satellites
You can easily observe satellites flying above your head with the naked eye, if three conditions are present:
The most visible satellite (excluding Iridium flares) is ISS (even mag -1.5). Other satellites, you can catch with the naked eye, are grouped in VISUAL.TXT TLE file.

Updating TLE files
    For accuracy of prediction your TLE files must be up to date, these files are available to download from www.space-track.org (only for registered users of Space-Track.org; registration is free) or www.celestrak.com. You can use TLE Updater, implemented in Orbitron Setup to perform this operation.
    It's difficult to determine maximum TLE age for perfect prediction. For satellites like ISS, you should update TLE every few days. For Iridiums, one-month updating is enough. NOTE: After each satellite maneuver, TLE data loses its validity. It's important for ISS, after shuttle docking or maneuvering new satellites. If you have Internet connection, just update your TLE files every day.

Time
    You need perfect time information. Your watch should be synchronized with a professional clock. You can set it using model signal emited at noon by national radiostations (in Poland - 1st Program of Polish Radio). In Orbitron 1.3 and above there is an Internet time synchronization via NTP. Try it in Setup. For naked-eye observation, a few seconds precision is enough; for flares observation, 1 second precision is nice; but when you use telescope, your watch should be synchronized in tenths/hundredths of a second.
NOTE: Time synchronization is a built-in function under Windows XP/2003 (Control Panel > Date and Time > Internet Time)

Your coordinates
    Your city coordinates (longitude/latitude) should be also exact for high precision prediction. To find them, you can use GPS, maps or check it on www.heavens-above.com

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