[neo_followup] {MPML} Improved 1964-054A = OGO-1 data, ephems

[Bill Gray]

Hi Sam, all,

On 8/28/20 6:19 AM, Sam Deen via groups.io wrote:
> 
> You'd think they'd have learned after two accidental finds just two days ago, wouldn't you?

    Well... that's mostly on me,  I'm afraid.

    For the first "find" of OGO-1,  I have a decent excuse.  We've
had pretty good TLEs and lots of data for this object for the last
five years.  Generally speaking,  we've known where it was.  But
during late August,  it had just enough drag to make it difficult
to predict.  I'd have told you that we just had rough guesses as
to where it might be.  For all I knew,  it might have already
re-entered.  The data were actually quite good -- thank you,
Goran Gašparović! -- but I wasn't too sure how well the theoretical
modelling of grazing atmospheric passes would match reality.

    As it turned out,  I was overly pessimistic.  The first
"find" was within about two degrees of prediction.  But
that wouldn't really have been close enough to be considered
a match,  and the object would have ended up on NEOCP anyway.

    For the second "find" (ZTF0ENg),  I don't have such a good
alibi.  If I'd posted TLEs from before the recent perigee
at 27.63 August,  with "guessed" AMR=0.03,  the object would
have been within 7' of prediction.  If I'd been quick about
posting TLEs after that,  we'd be good to arcseconds.  So
yes,  that one did slip by.

    The TLEs used for this identification are posted to my
GitHub site,

https://github.com/Bill-Gray/tles

    with the TLEs for this particular object updated a couple
of minutes ago.  MPC will pull those changes in a few hours;
after that,  the object ought to be safe from NEOCP posting.

    I should note that the tracking of such objects is indeed
somewhat "casual".  I get observations mostly from amateurs.
It's been a hobby for me.  Given all that,  we've been doing
reasonably well.

-- Bill