re: Earth Satellite Ephemeris Service

Walter Nissen (dk058@cleveland.Freenet.Edu)
Fri, 19 Jul 1996 13:21:55 -0400

> From: dedalus@latrade.com (Lew Gramer) 
> Subject: Re: Earth Satellite Ephemeris Service 
 
> Hi, John. I posted a query re: this Web site to seesat-l a while back, and was 
> basically told that it probably only covered a few of the brightest satellites 
> (which seems to be false) 
 
With 8000+ objects in orbit, the word "few" has acquired more than one 
meaning.  Few could be 3.  It could be 2000.  Depends on your perspective. 
 
> , and that the TLEs might or might not be fresh. Can 
> anybody who has USED this service (or tried to) provide any more reliable 
> feedback on it? 
 
I would sincerely hope that one of the principal(s) of the service will 
respond to this question. 
 
But, even absent that, anyone who has a "prediction" program can test the 
service.  For example,  Mir was deboosted between these two OIG elsets: 
 
Element set number = 1 
1 16609U 86017A   96185.24358254  .00001434  00000-0  24577-4 0  5780 
2 16609  51.6521  43.2619 0002226 151.4371 208.6742 15.58901052592486 
Element set number = 3 
1 16609U 86017A   96186.78127066 +.00000336 +00000-0 +10000-4 0 05815 
2 16609 051.6511 035.5379 0009907 266.5505 093.4215 15.61440175592722 
 
You could run "predictions" from a current elset; I'm currently using 
this one: 
Mir mine 
1 16609U 86017A   96199.45307441  .00002377  00000-0  33326-4 0 0610x 
2 16609 051.6522 331.6796 0010257 312.8948 047.1182 15.61513580594703 
and also from the service, for, say, a zenithal pass to obtain maximum 
accuracy, and then compare them.  If they are very different, that would 
suggest that a very old elset was used for one of the "predictions". 
 
Same idea, for an object that has been moved to a different orbit.

Cheers.

Walter Nissen                   dk058@cleveland.freenet.edu