Hi folks,

I'm late in replying to this because I decided that it's time I
wrote up something for the Web site on this topic:

http://www.projectpluto.com/ast_occu.htm

Use of a dataset such as MPCORB is actually not all that
helpful in cases such as this. The current data is for the
epoch 10 June 2003, about 75 days away. (MPCORB
follows the same 200-day spacing between epochs as the
built-in Guide elements do.) The current MPCORB will
include a few observations that Guide's built-in data lacks,
but not enough to change the results for these low-numbered
asteroids by very much.

As is described at the above URL, the only real solution
to get truly accurate results is to compute your own orbit,
for an epoch matching the actual event, using only the
"highest-accuracy" observations. (In practice, this means
the USNO FASTT data.) Using this data, and feeding it
through the Find_Orb orbit determination software, I got
this orbit:

Orbital elements:
(2060) Chiron
Perihelion 1996 Feb 8.096576 TT
Epoch 2003 Mar 29.0 TT = JDT 2452727.5
M 51.05020 (2000.0) P Q
n 0.01959021 Peri. 339.16215 -0.98781477 0.14396937
a 13.6283499 Node 209.30935 -0.12015629 -0.94689429
e 0.3812687 Incl. 6.93616 -0.09891629 -0.28751350
P 50.31 H 6.5 G 0.15 q 8.4322866
From 72 observations 1998 Mar. 21-2002 Jul. 11; RMS error 0.357 arcseconds

There! I've just done the hard part. Save this e-mail to a file,
fire up Guide, and click on "Extras... Add MPC Comets/Asteroids",
and select the file you just made. If you then "go to" asteroid
(2060) and click on it and ask for "more info", you'll see that you
get the above elements, with an epoch of the day of the actual
occultation. Then click on the target star, and ask Guide to show
you the eclipse. (Be sure that "full precision" is selected in the
"Data Shown" dialog; this is a very accuracy-demanding thing
we're attempting here.)

The resulting path is a bit south of other predictions. Problem
is, I think some more astrometry has been gathered since
June 2002 (see the above element set), and the other predictions
may include a better star position (I just used the Tycho-2 position
given by Guide). However, the uncertainty in these predictions is
so great that the above prediction may not be far off the mark.
It may even be right.

-- Bill