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Time label freq [  6   ]
Number of steps [ 100  ]
Add a Trail...
Clear Trails    Cancel

   With the above settings,  you would be telling Guide to show the
trail for an object at ten-minute intervals,  for 100 such intervals.
At every twenty minutes,  there would be an index mark (tick mark
crossing the trail).  There would be labels showing times along the
track at every sixth step,  that is,  for each hour.

   By default,  the "Round to nearest step" box would be checked.
This would mean that if Guide's time was,  say,  03:14:15.9,  this
would be rounded off to the nearest ten minutes,  and the starting
point of the trail would be 03:10:00.0.

   Also provided in the Add A Trail dialog is a button showing the
color in which the trail will be drawn;  you can click on that button
to select a different color.

   The "Clear Trails" button lets you erase all trails of moving
objects.  However,  as with so many things in Guide,  you can click
on a trail with the right mouse button,  then tell Guide what color
you want for that trail,  or delete it.

   Once this setup work is done,  you can click the "Add Trail" button,
and Guide will pause briefly to compute and display the trail in question.

   Guide will automatically save your trails when you exit the
program,  and will bring them back up when you restart the program.
The trails are stored as an overlay,  which means you can control
their display in the Overlay menu.  You can add text,  lines,  and
circles to the trails,  select the fields of view where they can be
shown,  and remove unwanted objects;  see the section on user
overlays on page 36.
                                                         
   The steps for creating an ephemeris for a solar system object are
very similar to those for creating a trail.  As before,  set the
current time to match the start of the ephemeris,  and right-click on
the object for which you want an ephemeris. Click on "Make Ephemeris",
and enter the number of steps and their size. Again, there's an option
to have the starting time rounded off to the nearest step size. Click
OK,  and Guide will compute the ephemeris and display it on-screen.
You can save the ephemeris to a file or print it,  much as you could
any other help/glossary/"more info" item.
                                                 
   By default,  Guide will provide some fairly useful data in the
ephemerides,  but you may want to provide different details.  For
example,  for an artificial satellite,  the alt/az may be of greater
interest than the RA/dec;  or you may want to list the percent of an
object that is illuminated.  In such cases,  it helps to click on the
"Options..." button in the "Make Ephemeris" dialog. This leads to a

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