Re: C* 2315 r obs by Walter Nissen, bad elsets for 92 80A

Mike McCants (mike@comshare.com)
Sat, 4 May 1996 17:49:59 -0500

Obs by Walter:
>95- 32 B 96-04-18  1:38:45.2 WN  234.3 1.5  18 13.02  A'A', C* 2315 r  (??) 
>95- 32 B 96-04-18  1:38:45.2 WN  155.7 1.5  12 12.98  A'A', C* 2315 r  (??) 
>95- 32 B 96-04-18  1:41:35.6 WN   63.9 1.    5 12.8   A'A', C* 2315 r  (??) 

Note that #1 1:38:45.2 + 234.3 = 1:42:39.5   Per 13.0 +/- 0.08
          #2 1:38:45.2 + 155.7 = 1:41:20.9   Per 13.0 +/- 0.13
          #3 1:41:35.6 +  63.9 = 1:42:39.5   Per 12.8 +/- 0.2

And start #3 1:41:35.9 - end #2 1:41:20.9 = 14.7

So, #1 = #2 + 14.7 + #3.

Unless the observer thinks that the 14.7 observation is when something
really unusual happened and that the before and after series are not
really properly related, they should all be combined and #1 reported.

My opinion is that nothing unusual happened and that the 13.0 period
agrees with the rest of the world and that the longest possible accurate
span (#1) should be reported.

Note that the reported accuracy is 1.5 seconds, but the potential synodic
effect of a 90 degree observed arc for a 13.0 second period could be as
much as 6.5 seconds.

Anonymous:
>I'd choose the middle one.  In general, my personal feeling is to avoid 
>timing more than ten flashes [or more than 90 degrees of sky] to minimize 
>the synodic effect.

The synodic effect is related to the apparent angular speed of the object.
It cannot be minimized by reducing the number of flashes in order to reduce
the actual amount of sky that the object covers while being timed.

One could minimize the synodic effect by making observations when
the object is very low in the sky and moving at a slower angular speed.
But I would recommend against this as a deliberate act.  :-)?

------
 
>Do you, or does anyone, believe the drag factors in these elsets? 
>Cosmos 2221      6.0  2.0  0.0  5.9 
>1 22236U 92080  A 96109.09381685  .00001449  00000-0  22019-3 0  9736 
>2 22236  82.5136  87.1715 0020362 205.2032 154.8033 14.73962359182787 
>Cosmos 2221      6.0  2.0  0.0  5.9 
>1 22236U 92080  A 96116.01825458  .00820039  00000-0  11673 0 0  9764 
>2 22236  82.5168  80.7761 0021441 182.3066 177.7790 14.74049108183800

No.  Maybe some other object in a similar orbit moved by it and confused
the computer program.  Here are the latest 5 elsets from OIG:

1 22236U 92080A   96120.97398468 +.00002690 +00000-0 +40515-3 0 09935
2 22236 082.5172 076.2003 0021656 166.1691 194.0105 14.73956953184533

1 22236U 92080A   96121.51707674  .00001788  00000-0  26816-3 0  9866
2 22236  82.5171  75.6986 0021607 164.6009 195.5825 14.73956174184616

1 22236U 92080A   96121.99228362 +.00000753 +00000-0 +11103-3 0 09910
2 22236 082.5170 075.2593 0021852 163.1485 197.0361 14.73953055184683

1 22236U 92080A   96122.94269680 +.00000612 +00000-0 +89516-4 0 09899
2 22236 082.5170 074.3821 0021910 159.9003 200.3074 14.73953660184828

1 22236U 92080A   96123.96099667 +.00000221 +00000-0 +30100-4 0 09899
2 22236 082.5172 073.4424 0022071 156.4677 203.7547 14.73952223184979

The object never changed in its very stable orbit.

It would seem that when the computer makes a mistake and introduces a bad
drag term, it takes many days for the program to exponentially return
the drag term to the correct value.  (I have seen this in the past.)

Mike McCants
mike@comshare.com