Two Iridium anomalies

Ed Cannon (ecannon@mail.utexas.edu)
Sun, 10 Jan 1999 03:29:57 -0600

First, on the way to a star party site about 90-100 km. northwest 
of Austin, from the car Geoff Chester spotted and I saw also what 
certainly looked like a very bright Iridium flare.  Geoff
estimated -5.  I don't have the exact time, but Iridflar gives no 
predictions +7 or brighter during the window of time when we saw 
this one.  I estimated that it was about 15-30 degrees up and 
320-340 azimuth.  So anyway, this was a very bright, unpredicted 
flare.

Second, on the other hand, we *did* have a prediction for a +1 
flare from Iridium 55 (25272/98-19A) at 19:39:50 local (1:39:50 
UTC on 10 Jan.), and none of us who looked saw anything at all.  

Here are the Iridflar predictions that I had for +7 or brighter.

Site name: Canyon of Eagles, Texas
Latitude:  30.88400  Longitude:  -98.43000  Altitude:  1200.0 ft
Time Zone: UTC  -6.0 h

      Local    Local     Iridium          Sun    Flare  Max Flare  Ir
Day   Date     Time    Azm El Rnge N I  Azm Elv Mag MMA  Bearing    # S
-----------------------------------------------------------------------
Sat 99- 1- 9 18:03:10  203 30  848 D L  246  -3   1  R  29.9 mi E  22  
Sat 99- 1- 9 18:12:45  210 23  991 D L  248  -4   5  R   104 mi W  23  
Sat 99- 1- 9 19:22:10  284 07 1605 D L  255 -19   7  F     N/A     26  
Sat 99- 1- 9 19:31:50  159 16 1217 D L  256 -21   6  R   165 mi E  60  
Sat 99- 1- 9 19:39:58  163 25  953 D L  257 -22   1  R  29.8 mi E  55  
Sat 99- 1- 9 19:49:05  174 26  922 D L  258 -24   5  R   105 mi W  28  
-----------------------------------------------------------------------

During the evening I saw a few one-power flashes from Iridium 27
(24947/97-51D) at about 2:03-04.

I think that this was one of the coldest nights of observing that 
I've experienced (along with the recent Geminids maximum) -- about 
25 deg. F (-4 C) -- but it was very dark and clear!

Ed Cannon - ecannon@mail.utexas.edu - Austin, Texas, USA