<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>No, Iridium lasts for about 6 seconds. It starts out slow, grows really bright, and then fades off. The ground track is about 30 Km wide. That is about 20 miles. Low Earth orbit is about 5 miles per second. That would give a duration of 4 seconds. Add a second on each end for diffraction and inaccuracies and that would put us right in the 6 second arena.PS - Always be cogent of the flashes coming up in your area. Carry a calibrated watch and know your directions. As you sit with a prospective girlfriend, client, employer, you can always say: "I can make a star appear." Look right about over there in about 5 seconds." It has worked wonders for me. <br />Posted by billslugg</DIV></p><p> </p><p>Yes Iridiums allow you to amaze your friends and enemies. </p><p>The timing also depend on how high in the sky they are. From 45 degrees and up, the spot is indeed quite small, but ones lower on the horison, while not as bright due to passing through more air and a greater distance, can last quite a bit lomger since the spot is spread into a larger ellipse as it intersects the earth at an angle.</p><p>With binoculars, you can see Iridiums for quite a while before and after the Flare as well.</p><p>It is also often useful to look at that same spot about 10 minutes before and after with binoculars. You can often see the leading and trailing Iridiums, that don't get as bright.</p><p><br /><br /> </p> <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>