Aw: Re: Question about the age of available TLEs

From: James Lloyd via Seesat-l <>
Date: Sat, 10 Feb 2018 23:52:58 +0100
Hello to all,

well, I think we shouldn't neglect the contribution of Mike McCants, especially his file named :

Kind Regards,

> Gesendet: Samstag, 10. Februar 2018 um 20:12 Uhr
> Von: "Gavin Eadie via Seesat-l" <>
> An: "Charles Phillips" <>
> Cc:
> Betreff: Re: Question about the age of available TLEs
> > On Feb 10, 2018, at 1:25 PM, Charles Phillips <> wrote:
> > 
> > Isn't the source of most site's TLEs the Space-Track site? I believe (as you say) that CelesTrak and Heavens-Above get TLEs from Space-Track. There is a NASA site for ISS vectors and probably a TLE as well. For the "official" satellite catalog there is not another source. 
> I’m sure you are correct in saying Space-Track is the ultimate source for all TLEs, except that for the ISS.  In that case NASA offers a small sequence of TLEs (on the "state vector" page) to cover the next several days.  Heavens-Above appears to use those, and not Space-Track's.  Why they then use a TLE set with an epoch getting close to two days in the future is another question!
> > That being said, the quality of TLEs from Space-Track does vary; I discard any "future epoch" TLEs that they publish. Hopefully other sites also discard those TLEs.
> I tend to use Celestrak TLEs believing Kelso does a good job of dropping out anomalous elements.
> > I await other comments. 
> Me too, though since ISS is the only object with more than one source of elements, and not exactly hard to find during a pass, and the difference found between the two sources is minor, I’m know I’m not highlighting anything of significant practical concern!
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Received on Sat Feb 10 2018 - 16:53:58 UTC

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