Re: epoch

Pouplier Alphonse (
Tue, 11 Mar 1997 16:41:28 +0200

>>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?

Tony Beresford:
>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.

OK but does it correspond to a date when the TLE's were made?

My pleasure, avec plaisir,  Alphonse
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