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Re: 2 line element question

-----Original Message-----
From: Jeff Johns <jeffj@scott.net>
To: amsat-bb@AMSAT.Org <amsat-bb@AMSAT.Org>
Date: Sunday, December 20, 1998 9:03 PM
Subject: [amsat-bb] 2 line element question

>In a standard 2 line element set, is there a simple way to look at it and
>tell the date of it. In other words, if I was looking at 2 two line element
>sets for the same satellite, how can I tell which is the latest without
>actually reading it with tracking software?

Yes there is.  Note the set of Keps below for the ISS:

1 25544U 98067A   98354.70606037  .00023986  00000-0  33222-3 0  1410
2 25544  51.5949  14.5798 0004068 279.8581  80.2041 15.56948353  4768

The epoch [date and] time is: 98354.70606037

That is year 98 (i.e., 1998),
The 354th day of the year (i.e., 20 December)
and the fraction of the day 0.70606037 (equivalent to 08 hrs, 28 min, 21.808

The year and the day should be enough unless you have two with the same day.
If you have two with the same day, the one with the larger fraction is newer
don't need to convert to hrs, min, sec to tell.

Hope this helps.

73, Ken N2WWD

Ken Ernandes

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