Oh, yes... should have mentioned: time zone set on your
computer should be utterly irrelevant. The only time Charon
will be using is the one from the FITS header, which is
assumed to be in UT. (FITS doesn't provide any way of specifying
any other time zone. If it used the zone to which your
computer is set, we'd all be in trouble: you could capture
an image on your machine set to local time, send it to
somebody else set on UT, and they'd have no way of knowing
the 'real' time the image was taken.)

Also, a small point: prompted by Chris' inquiry about
setting up an unofficial MPC observatory code, I made a little
fix so one could add a code to 'obscodes.htm' such as

Z00 -69.9 44.01 100 Project Pluto Corporate HQ

The three-letter abbreviation and the observatory name are
in the same places as any other code designation. But instead
of providing a longitude and parallax constants, one gives
the longitude, latitude, and altitude in meters. This
gets around the problems of dealing with parallax constants.
This fix is present in the update I posted at

http://home.gwi.net/~pluto/charon.zip

-- Bill