Re: epoch

Anthony Beresford (
Tue, 11 Mar 1997 23:52:09 +1030 (CST)

At 10:53 AM 3/11/97 +0200, Alphonse Pouplier wrote:
>I have a question:
>In the 2d line (21-32) of the "two-lines" TLE's
>the reference day (epoch) is given with 8 decimals.
>thus to .000001 of a second.
>I presume those TLE's are made from several observations.
>Is the given epoch the one of those observation?
>My pleasure, avec plaisir,  Alphonse
Alphonse, the epoch is the time of an equator crossing. If you
look at the TLe's of objects in low eccentricity orbits you
will see that the sum of the mean anomaly and the argument
of perigee is always very close to 360 degrees.
Tony Beresford