Iridium 27 and 28 observations

Alexander Seidel (
Sun, 11 Jan 1998 18:50:39 +0100

With another clear night over Central Europe, I was able to observe both
Iridium 28 and the new "strober" Iridium 27:

Iridium 28 (97-51 E, #24948) was expected to flare with mag -2.8 from my
location, at az 49 deg and alt 60 deg, angle 0.58 deg. It did so right
on time, but I am inclined to give it an even brighter estimate of at
least mag -3.5 at the peak of the show, which lasted 10 sec for the
naked eyes.

A few minutes later Iridium 27 (97-51 D, #24947) made a pass high up in
the east (alt 82 deg). I saw it with 7x35 binocs and timed 5 sharp
flashes, decreasing from mag +1 to mag +2.5, with a 100-lap-times
stopwatch at (rounded to 1/10th sec):

		UTC 16:54:09,0
		UTC 16:54:12,5
		UTC 16:54:16,1
		UTC 16:54:19,7
		UTC 16:54:23,2 

This gives a flash period of 3.55 (approx. +/- 0.05) seconds, in good
agreement with the observation which Leo Barhorst made yesterday from
his location in Alkmaar, Netherlands.

Alexander Seidel        N53.5932 E9.4683  6m asl
Stade/Germany           Tel/Fax (+49) 4141 68772