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

[Bill Gray]

Hello all,

    I found quite a bit of additional data for this object in
my inbox this morning (thank you!).  At present,  I've got
46 observations from the current orbit :

https://www.projectpluto.com/temp/ogo1.txt

    A correction to my previous e-mail : you can just download
the above file and feed it into Find_Orb,  either "current"
Windows or Linux,  or on-line,  or the old Windows GUI version,
and compute ephemerides for your location that should be good
to within a few arcminutes.  That's about the level of effect
I expect the upcoming perigee (occurring as I write) to have.

    You can still turn on solar radiation pressure (by hitting
the '*' key) and constrain the area/mass ratio to be A=0.03,
and get suitably adjusted results.  But unless you have a
small field of view,  the non-SRP version should at least let
you find the object.

    The good news is that,  if the nominal AMR makes a five
arcminute difference (300") and the object is measured to an
arcsecond,  it means the effects of atmospheric drag during
that pass will be measured to about one part in 300.  Which
is pretty good.  And we'll probably get enough data to
_really_ nail down the re-entry time and location.
(Currently looks to be at about 21:00 UTC on the 29th over
French Polynesia,  but a little more or less drag could
make that prediction look stupid.)

    This may be a useful exercise to prepare for something
like the 1972 fireball that zipped through the atmosphere,
lost lots of speed,  and probably was left in Earth orbit
and crashed at the next perigee.

-- Bill