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and alt/az.  Entering coordinates is a fairly common task, so in
Guide you can do it in several ways.

   If coordinates in any of these systems are shown in the Legend, you
can just click on those coordinates and Guide will prompt you to enter
new coordinates.  For example,  if the RA/dec is shown in the legend,
you can click on it and Guide will ask for a new RA/dec.  If the
altitude/azimuth is shown,  you can click on that and Guide will ask
for an alt/az position,  and so on for the other coordinate systems.
                                                                 
   Also,  you can select any of these coordinate systems from the
Coordinates menu,  under the Go To menu.  The Coordinates menu
also has an "Opposition Point" option,  to find the point directly
opposite the sun.
                                                           
   When entering an alt/az position,  you will be asked to enter the
altitude first.  This can range from -90 (straight down,  the "nadir")
to zero (a point on the horizon) to 90 (straight up,  the zenith).
Next,  you will be asked to enter an azimuth,  or "bearing".  This can
range from zero (due north) to 90 (due east) to 180 (south) to 270
(west) to 360 (north again). Guide will then recenter on the position
given. A description of alt/az is given in the Appendices,  on page 79.

   If the coordinates aren't being shown in the legend,  or if you want
other coordinates such as ecliptic or galactic to appear in the legend,
you can toggle them on quite easily.  This is described on page 25.
                                     
   A comment on entering RA/dec positions.  Guide is quite willing to
accept the many forms of RA/dec coordinates;  for example,

   10h42m36.00s            N41.69
   10h 42m 36s             N41 41' 24"
   10 42 36                +41 41 24
   10h 42.6m               N41 41.6'
   10.71h                  +41 41' 24"
   104236.0                +414124

   all refer to the same position in the sky,  and all will be correctly
understood by Guide.  You can leave out minutes or seconds, put spaces
between fields,  use +/- in place of N/S, and use decimal amounts.  If
Guide can't figure out what you meant,  it will tell you so with an
error message,  and will give you a chance to try again.

   You can also indicate if the RA/dec you are entering is in the J2000,
B1950,  mean,  apparent,  or other epoch.  Most of the time,  you will
probably be entering J2000 coordinates.  Some older data is given in
B1950,  and in rare cases,  you may need to enter coordinates in one
of the other epochs. (The concept of an "epoch" is explained in the
Appendices, page 77.)

   Note that this allows you to set the epoch of the coordinates you're

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