RJ@RMATSC.RIEM.COM schrieb: > The width and length of a perfect Iridium flare can be calculated as > follows: > > dist = distance from the observer to the sat > alt = angle from observers horizon to the sat > 1/2 = angular diameter of the sun > > width = dist * tan(1/2) > length = width / sin(alt) > > For an Iridium whose distance is 1200 km and 30 degrees > above the horizon the flare width would be 10 km and > length 20 km. > > Real flares are far from perfect however. There is no sharp line > between light and dark and the actual flare spot would be both > larger and fuzzier. > > The velocity of the flare is much harder to calculate but it would > be of the same order as the velocity of the spacecraft. > > Randy > > > > -----Original Message----- > > From: jmonseur%mail.cpod.fr%cds.plasma.mpe-garching.mpg.de@Mail.Riem.Com > [SMTP:jmonseur%mail.cpod.fr%cds.plasma.mpe-garching.mpg.de@Mail.Riem.Com] > > Sent: Tuesday, February 03, 1998 5:46 AM > > To: SeeSat-L%cds.plasma.mpe-garching.mpg.de@Mail.Riem.Com > > Subject: Iridium Flares ground projection > > > > Good morning all, > > > > To Rob.Matson, Randy John or anybody knowing: > > > > Could one see an Iridium flare projection moving on the ground > > or on the sea, e.g. from a plane or from a cliff ? > > > > What would be its width ? its speed relation with the sat ? > > > > Many thanks. > > jm > > jmonseur@mail.cpod.fr Tel. 0231 85 55 19 > > GPS Lat. N. : 49d 11' 8.65" Long. W. : 0d 22' 41.2" Alt. : 48 m >