Iridium 11 and 14

Matson, Robert (
Wed, 28 Oct 1998 20:07:54 -0800

Hi All!

Just a quick note to encourage everyone to keep those Iridium 11
and 14 flash times coming!  I've reduced all the data so far from
Richard Keen, Bjoern Gimle, Jim Nix, Don Gardner and Ed Cannon,
and a pattern is beginning to emerge -- more so for 14 than 11.  The
specific info that I need for my analysis is the UTC date/time of
the brightest flash for each sequence of flashes observed.  For
example, sometimes you'll get 4 or 5 consecutive bright flashes
at the rotation rate (e.g. 5 seconds apart); in this case, I'd want
the time of the central flash of the group (or, if it's an even # of
flashes like 4, the time time halfway between 2 and 3).  If you
then get a period of no flashes (or only dim ones), followed by
another series of bright flashes, I'd want the central time for that
series as well.  You could have as many as 4 separate bright
flash cycles on a single pass of the satellite.

Now, on those occasions that you get a long string of flashes
that are all in the same brightness ballpark (Ed's string of 44
comes to mind), then just give me the start and end times of
the sequence.

Once I've got enough data, I may be able to work out the spin
axes for these satellites.  Same goes for Iridium 24 (sometimes
referred to as 46), Iridium 27 and Iridium 71.

So far I have 42 data points for Iridium 11, 16 data points for
Iridium 14, and 37 for Iridium 27.  Unfortunately, many of IR11's
points were from a time when it was tumbling, so that data will
not correlate to current measurements.  (IR11 appears to be
a bit better behaved right now, which means it may be settling
down into a stable spin axis).

Thanx!  --Rob

P.S.  Eurosom 3 was a great success!  I really enjoyed meeting
everyone that attended!  I haven't seen it reported here yet, but
several optimistic Seesaters came prepared with Iridium predictions
(Bjoern Gimle, Paul Maley, Jay Respler).  Our weather was quite
good on Friday, Sunday and Monday -- so much so that the entire
group got to see a -7 or -8 daytime flare from Iridium 57 on Sunday
afternoon!  How's that for long-range meeting planning?