re: Cerise elements

Walter Nissen (dk058@cleveland.Freenet.Edu)
Tue, 13 Aug 1996 20:50:03 -0400

Allen Thomson writes: 
 
>    With regard to the AWST report of a collision between Cerise 
> and an Ariane fragment in late July 1996, here is my collection 
> of Cerise elements for that time.  Just looking at the mean 
> motion derivative, it seems as if epoch 96210.78 is the 
> anomalous one. 
 
In terms of ndot2, that is true.  (I recall an elset for Mir with an 
ndot2 of .55).  But in terms of MM, the anomalous one has epoch 96212.07. 
 
Maybe someone with some convenient software can tell us if there is an 
anomaly in MA.  I could wish there were some DOS software to compute 
"derivatives" of all these quantities and/or spot elsets which jump out of 
a uniform line.  While this may occur to me as a parenthetical thought, 
it isn't just an idle thought.  Some notice has been taken of the problem 
of anomalies in the vast stream of elsets generated by SPACECOM alone. 
What I am saying here is not in any way intended as a criticism of that 
extremely extensive effort.  But Bjoern Gimle and I have asked ourselves, 
"If we occasionally notice prominent errors, such as epochs many months in 
advance, or bizarre ndot2's, what does that suggest about the elements we 
can't or don't notice"?  Like MA or ArgP or bstar, in my case, or others. 
The ndot2 problem is extensive enough that Ted Molczan munges them in his 
file.  I haven't extensively checked, but based on sparse evidence, that 
seems to be somewhat successful.  These errors form a background against 
which to observe changes which may be real, such as those sought by Kurt 
Jonckheere; see SeeSat-L message 2148 and many others. 
 
> 1 23606U          96209.55262140  .00000054           18109-4 0  2409 
> 2 23606  98.1022 145.8692 0009104  56.7984 303.4095 14.67264765 56631 
> 
> 1 23606U          96210.78012517  .42281232           60776-1 0  2068 
> 2 23606  98.1039 147.0843 0008886  60.3283 299.8805 14.67265738 56818 
> 
> 1 23606U          96211.46207215  .00000442           87023-4 0  2170 
> 2 23606  98.1031 147.7571 0008828  57.9183 302.2887 14.67267229 56919 
> 
> 1 23606U          96212.07582686  .00000515           10000-3 0  2335 
> 2 23606  98.1027 148.3633 0008860  55.1373 305.0626 14.67212094 57000 
> 
> 1 23606U          96212.55318801  .00000338           68594-4 0  1989 
> 2 23606  98.1030 148.8358 0008824  54.3848 305.8180 14.67267427 57071 
 
Cheers. 
 
Walter Nissen                   dk058@cleveland.freenet.edu 
 
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