Double flash from Iridium 65 (solar array flare)

From: Matson, Robert (ROBERT.D.MATSON@saic.com)
Date: Sat Jun 15 2002 - 16:08:35 EDT


Hi Willie and List,

> Regarding double Iridium flashes, I too since saw a double Iridium
> flash which I cannot explain.  I gave a satellite talk to about
> 60 people last Saturday night from a very dark site and noticed
> that we had a -2 mag flare from Iridium 65, scheduled about 20
> minutes into the talk. ... we even managed to pick up the
> satellite long before it flared (did I say it was a good site?)
> and followed it to the predicted flare point where it did its
> thing.  Just as the applause and the satellite started fading,
> it almost immediately flared up again as it missed Alpha Cen
> by 2 degrees (where was my camera?).  Since I was trying
> to keep my pose through all the cries of "why", I did not
> make a mental note of the brightness of the 2nd flare but
> it came close to the first, perhaps a little fainter.

As has been suggested by Bjoern and others on the list, you saw
a solar array flare from Iridium 65.  It was predicted to be
magnitude -3 by IRIDFLAR, 25 seconds after your regular flare
from the right MMA.  Solar array flare prediction was added (with
a fair degree of programming effort!) in IRIDFLAR version 2.2
about a year ago.  Surprisingly, few people seem to have made
attempts to observe them, probably because most people use
Heavens-Above for flare prediction.

Best,
Rob

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