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   Once you have set the desired rate, you can click on the
double-arrow "animate forward" button in the Animation Dialogue, and
solar system objects will start to move.  You can then click on the
central "stop animation" box when done.  The remaining arrows allow
you to run the process backward,  or to take single steps in time
forward or backward.

   For your first few efforts, you will probably do well to start
with a small step size and work your way up. You can also run
animation in "real time" (the objects move according to the actual
time, as provided by the computer's built in clock) by clicking on
Real Time.  When you do this,  Guide will ask you how often the
display should be updated.  (If you're following a rapidly moving
artificial satellite,  it may be necessary to update its position
once a second when in Real Time mode. But when following a
slower-moving asteroid or planet,  an update rate of once a minute
or even less may work nicely.)  Clicking on "Real Time" again
returns you to your previous rate of animation.

   Calculating planetary positions is time-consuming (especially on
machines without a math chip), so Guide may not respond in a
lightning-fast manner to mouse clicks when animation is running.
You may need to hold down the mouse button for a little longer than
usual when animation is in progress, in particular when you're
zoomed in far enough to see planets as disks.  The math involved in
accurate portrayals of planets (showing the correct side of the
planet, illuminated properly,  with shadows cast by other moons or
planets on the object) can be quite time-consuming.  You may want
to right-click on such planets and turn off their bitmaps;  this is
described in the section on planet display,  at page 21.

   The animation dialog contains four extra,  very important buttons:

(*) RA/dec
( ) Moving
( ) Horizon
( ) Proper motion

   In RA/dec mode,  the default,  the center RA/dec of the screen
remains unchanged while animation proceeds,  so that stars do not move.

   The use of the remaining buttons is a little complicated,  but a few
examples will make it quite clear.  It's recommended that these three
options be used with "Direct to Screen" (page 17) left unchecked,
to avoid an unpleasant "flickering" effect.

   First,  zoom in on Jupiter at level 12,  and set the animation rate
to about 15 minutes.  Click on Jupiter with the right mouse button (the
"get info" button),  and click "OK" in the resulting dialog box,  much
as you normally might. Now click on the "Moving" (Target) option in the

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