Iridium orbital planes question + 91- 19 B = 21153

Kurt Jonckheere (kjonckheere@unicall.be)
Thu, 13 Nov 1997 20:06:40 +0000

hello,

Taking a look at the iridiums.tle file of Alan Pickup I found that
the Right Ascensions of the Ascending Nodes (the orbital parameter
which gives the direction of an orbital plane referenced to the
vernal equinox) of the different orbital planes of the Iridium 
Constellation are  (in degrees) : 6 ; 37 ; 69 ; 100 ; 132

As there need to be 6 operational planes, I though the difference
between the planes should be ( 180 / 6 ) = 30 degrees.  

But this seems to be about 31 degrees.

Anybody knows the reason for this ?


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91- 19 B = 21153 still accelerating ? (observations of Jim Scotti
and Leo Barhorst added)
Who makes the next observation ?

91- 19 B 97-10-27 17:57:12   LB   89.9 0.5   4 22.5   AA, mag 4->inv
91- 19 B 97-10-27 17:58      KJ  319.1 0.5  14 22.8   mag 4.5->inv
91- 19 B 97-10-28 18:25:24   LB  113.9 0.5   6 19.0   AA, mag 3->inv
91- 19 B 97-10-29 18:53      KJ  142.4 0.8   8 17.8   mag +4.5->inv
91- 19 B 97-10-29 18:55      KJ  148.6 0.8   8 18.6   synodic effect
91- 19 B 97-10-30 17:36:00.4 KJ  179.8 0.5  10 18.0   FF, syn eff
91- 19 B 97-10-30 17:38:50.9 KJ  182.2 1.0  10 18.2   AA, syn eff.
91-019 B 97-11-02 01:37      JSC 142.8 0.5   9 15.9   A_, mag 4->inv
91- 19 B 97-11-09 16:52:39   LB  131.3 0.2   8 16.42  FF, mag 4->inv

latest from OIG : 21153
1 21153U 91019B   97316.00591015 +.00000576 +00000-0 +58743-3 0 09498
2 21153 082.9210 121.5875 0033097 328.2032 031.7126 13.74880076334764

Greetings,

Kurt Jonckheere