[neo_followup] EMM (Hope) tracking : spacecraft, booster, two other objects

[Bill Gray]

Hi folks,

    I've received astrometry from Masayaki Suzuki for the EMM booster,  as
seen from (U69) Auberry in California;  from Peter Birtwhistle;  and from
another observer who would prefer I not distribute astrometry quite yet,
as the data aren't quite final.  But that extra data confirms that the
following should produce good ephemerides.

    Peter got not only the booster,   but the spacecraft and other objects
all at close range.  My guess is that the spacecraft and booster should be
easy to find tonight,  with the booster visible for days.  The other objects
are getting a little faint and are probably lost at this point.

    The booster data show some "maneuvering" as venting of leftover propellant
(I assume) took place.  Putting together Masayaki Suzuki's data with the last
two observations from (J95) gets results that should be good to a few
arcminutes.  (Peter got plenty of earlier data,  but the venting caused
large residuals when combined with Masayuki's data.)  Cut and paste the
following into Find_Orb (on-line or "local"), and you should be able to
generate ephemerides for the booster.  (The program will automatically combine
the 80-column and ADES data.  I added some synthetic observations to help the
program find the correct orbit.)

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

    The booster should be visible for the next few days.

    Similarly,  you can cut-and-paste the following astrometry from Peter
into Find_Orb to get ephems for the spacecraft.  (Or you can use Horizons,
which is only off by an arcminute or so.)

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

    Peter tracked two additional objects that you'll need a good-sized scope
to see now (about mag 21.5 and 22.2 at this point.)

https://www.projectpluto.com/temp/emm3.txt
https://www.projectpluto.com/temp/emm4.txt

    And Peter got four other objects,  but they're down around mag 23 at
this point,  so I'd abandon all hope for them.

-- Bill