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 [ ] Line of variation (in days): 

 [ ] Show all asteroids 
 Show first [      ] 

   The labelling options allow you to have asteroids labelled only
by number;  by number or provisional designation (such as "1997 XF11",
the sort of designation used for asteroids that haven't been numbered
yet);  or by name or provisional designation.
                                             
   The "Use MPCORB" option is grayed out by default.  It allows you
to switch between Guide's built-in asteroid data,  or data from the
MPCORB dataset.  The MPCORB file is available at:

http://www.minorplanetcenter.org/iau/MPCORB.html

   Guide has a copy of MPCORB built into the DVD.  This copy will
provide a list of asteroids known at the time the DVD was made,
which may be enough for you.  But if you're interested in more recent
objects (or objects whose orbits may have been updated since the DVD
was made),  then you should visit the above site and get a copy of
MPCORB.DAT and put it in your Guide folder.  Guide will then use that
"local" copy in preference to the one originally supplied with it.

   Toggling the "Use MPCORB" check-box will cause Guide to use the
elements in MPCORB, while ignoring the asteroid data built into the
Guide disk.

   Switching to MPCORB has advantages and disadvantages,  and it's
important to understand both.  If you don't use MPCORB (the default),
Guide can make use of a lot of pre-computed data regarding where each
asteroid will be over a given time and how bright it will get;  this
allows Guide to display asteroids almost immediately (as long as your
"location" is on Earth).  Elements are provided covering a range of
several decades,  so perturbations are modelled with good accuracy
over that entire range.  Also,  only the first 100000 asteroids are
given (as opposed to the full half-million from the MPCORB file).
For most purposes,  that first hundred thousand is more than enough.
But if you're looking at fainter asteroids,  you'll need to switch
to MPCORB.

   Also,  of course,  the "built-in" asteroid data can't be
rewritten. You're stuck with the data as it appears on the DVD,
and newly discovered asteroids (and orbits updated based on new
data) will not be included.  This is where MPCORB has a great
advantage; the MPC updates it almost daily.

   People engaged in asteroid discovery and astrometry (measurement
of positions) will find MPCORB to be just about essential,  and will
accept the fact that it slows Guide down significantly. Such people
are also usually concerned only with "current" information, so the
fact that perturbations are ignored when MPCORB is in use will not

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