Re: Milstar and Centaur

Jason Hatton (hatton@naxos.unice.fr)
Mon, 3 May 1999 13:54:17 +0200 (MET DST)

Phillip Chien wrote

>In any case the Milstar and Centaur will certainly be very interesting
>visual objects, even at medium latitudes.  Centaurs are extremely
>interesting objects to view, and there are only a handful of them at low
>altitudes in roughly circular orbits (Centaur 2, HEAO, SAX).  This
>particular Centaur is 14' in diameter in comparison with the 10' diameter
>ones used with Atlases.
>Currently no elements are available from OIG for either object so this
>looks like an excellent opportunity for the amateur observers to find these
>objects and amateur orbital mechanics community to derive the orbit.  I
>would be especially interested in looking at any element sets for search
>orbits.

All of the Centaur G' upper stages launched by Centaur IV's are currently
classified objects, so it is not possible to obtain elements directly from
OIG. I did observed one of these objects last year which had been found by
amateurs (I don't remember which one, I don't have my observing log at hand
at the moment). It was a good flasher, much like the Atlas Centaurs, but
with a sharp double flash in each period. It was flashing up to about
magnitude +8 at a range of 20,000km, so the Milstar Centaur could easily
reach naked eye brightness from it's low altitude orbit.

If somebody can guess a preliminary orbit, I would certainly have a go at
trying to make positional & flash measurements of this potentially
interesting object.

Best wishes & clear skies,

Jason






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Jason Hatton
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