Re: 92 86C as Rick Baldridge's bright unknown

dmbrierley@taz.dra.hmg.gb
Thu, 6 Aug 1998 14:43:13 +0000

Mike McCants wrote:
> I have taken the past positions and elset for 92 86C and tried to
> fit Rick's observation.  I have come up with:
>  
> 92 86C - 7
> 1 99991U 9208603  98216.18567893  .00000700  00000-0  14746-3 0    03
> 2 99991  56.9257 235.4181 3385266  51.8850 308.1150  8.43363396    00
> 92 86C - 13
> 1 99992U 9208603  98216.18566278  .00001300  00000-0  25884-3 0    01
> 2 99992  56.9260 235.2590 3380000  51.9560 308.0440  8.43831574    05
> 92 86C - 19
> 1 99993U 9208603  98216.18564552  .00001900  00000-0  34248-3 0    04
> 2 99993  56.9257 235.0999 3385266  52.0270 307.9730  8.44308109    05
>   
> These 3 elsets have rather different mean motions because the
> old elset could be fit to the current observation using any
> one of the possible drag terms: 0.000007, 0.000013, 0.000019.
> (Also higher multiples of 0.000006, but I hope that its drag has 
> not been that high.)
>                     
> The difference in mean motion amounts to about 1 minute per day,
> so if a prediction is generated using the "13" elset, the object 
> should be within a few minutes of the predicted time.
>  
> The actual RA of ascending node is not well known, so the 
> object could also be several degrees east or west of the 
> predicted position.

I thought I'd warn observers that IMHO 92-86C is not the easiest of 
objects to acquire.  It seems to have unusually long minima, which 
can be 4 or 5 magnitudes below the maxima, lasting for periods of 
two minutes or more.

Happy hunting!


David Brierley
Malvern, Worcestershire, UK
Station 2675, 52.1358N, 2.3264W, 70m