A number of web-based programs
now exist for you to calculate when and where to see Earth-orbiting
satellites from your location―even to show their paths graphically
against the stellar background.
Before searching for satellites, be sure to
set your watch to the exact time from the
United States Naval Observatory. Often local phone
companies have a number one can call for a recorded time signal as
well. For example, in the San Diego, California area, one can call
One of the best
online sources for celestial information is
Heavens Above. You can use
it as a "guest", or you can "register"―both free. The advantage of
registering is that you can store information at the site (e.g.,
different observing locations, etc.).
Visit the website and click on "Selecting from our huge database".
From here you can select your city, and then follow the directions
to get information on satellites passing overhead, complete with
exact timings and a star map showing the satellite's path through
the constellations! Also available are data on sunrise and sunset
times, constellation maps and much more.
This site will also tell you when and where to view glints of
sunlight (flares) off of Iridium satellites. For these, you must
enter the exact latitude and longitude of your location, not
just the approximate coordinates of the city you're in. If
you don't have a GPS to get that information, you can type in your address
here, click on
Latitude/Longitude", and write down the
decimal form of your coordinates.
Next, return to
Heavens Above and click on
"Enter your coordinates manually". Follow all directions and then
select "Iridium Flares" (or any other calculation you desire). If
you've registered, you won't have to re-enter your coordinates each
time you return.
One final tip: always begin satellite searching at least 5-10 minutes
early... just in case!