Iridium flare pair was single

Bjoern Gimle (bjorn@tt-tech.se)
Thu, 23 Oct 1997 12:27:19 +0100

Early Monday evening I tried this flare pair (times are UT+2) :
11 97-10-20 17:57:47.0 191.6 49.2 18h35  18.9   978.7 D Lit  -4.2   4.86  2.1
11 97-10-20 17:58: 4.3 189.3 43.6 18h40  13.1  1055.9 D Lit  -4.2   0.04 -5.5
11 97-10-20 17:58:25.0 187.4 37.9 18h44   7.3  1158.3 D Lit  -4.2   4.84  2.4

13 97-10-20 17:58:12.0 191.2 49.2 18h37  18.8   997.9 D Lit  -4.2   4.77  2.1
13 97-10-20 17:58:29.4 189.0 43.7 18h41  13.1  1075.4 D Lit  -4.2   0.17 -5.4
13 97-10-20 17:58:50.0 187.1 38.0 18h46   7.4  1177.0 D Lit  -4.3   4.73  2.4

Only Irdm 13 was seen, and it was brilliant. It was behind a tree top, but
so easy to see, that I shouldn't have missed Irdm 11.
Furthermore, a friend of mine at Latitude:  59.55  Longitude:   18.16
saw only one of them (no exact timing)

I seem to recall another report of one expected flare missing,
but couldn't locate it.

We could expect missing predicted flares, or finding unexpected ones,
from Irdm 27 and/or 36, if they have attitude control problems, but
they also give us additional chances of seeing flare pairs, before a
new cluster is launched.

When I said that all others are at MM=14.34, I forgot no.11,
with MM=14.39, 16 km below the others, and no.21.
Orbital spares, and/or not properly controlled? Iridium 11 is not mentioned
on the http://www.satellite.eu.org/iridium.html pge, but the
other three are.

Did anyone observe it according to predictions recently ?
Ron's table in /iridrpt.html is not updated further than Sep.30.

Iridium 11       3.0  0.0  0.0  6.0 d            762 x 761 km
1 24842U 97030G   97293.01511110  .00001206  00000-0  38347-3 0  1347
2 24842  86.3887 110.3241 0001025 134.8669 225.2605 14.39174125 17804
Iridium 21       3.0  0.0  0.0  6.0 d            643 x 629 km
1 24873U 97034E   97293.09673593  .00000444  00000-0  58116-4 0   885
2 24873  86.3959 139.6633 0010195 243.8230 116.1940 14.77905104 15146
Iridium 27       3.0  0.0  0.0  6.0 d            564 x 549 km
1 24947U 97051D   97294.77213122 -.00011391  00000-0 -83964-3 0   748
2 24947  86.6403  46.1990 0010689 123.9198 236.3051 15.03506702  5689
Iridium 36       3.0  0.0  0.0  6.0 d            567 x 546 km
1 24967U 97056C   97294.44706286 -.00023161  00000-0 -17086-2 0   375
2 24967  86.7020  78.2999 0014897 148.5064 211.7122 15.03436917  3664

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