<MAINMENU>
	      MAIN MENU
   Move the highlight with the arrow keys
 then make a selection with the ENTER key.

<EDITMASS>
	     MASS
   Enter the mass of the planet
 in Kilograms (Kg).  The number
 given must be greater than or
 equal to zero.

<EDITDENS>
	      DENSITY
   Enter the density of the planet in
 Kilograms per cubic Meter (Kg/M^3).
 The value given must be greater than
 zero.  The density of water is 1000
 (1E03) Kg/M^3.

<EDITX   >
	 X POSITION
   Enter the X position of the
 planet in Meters.

<EDITY   >
	 Y POSITION
   Enter the Y position of the
 planet in Meters.

<EDITVX  >
	   X VELOCITY
   Enter the X component of the
 velocity in Meters per Second (M/s).

<EDITVY  >
	   Y VELOCITY
   Enter the Y component of the
 velocity in Meters per Second (M/s).

<EDITTRAC>
	      ORBITS
   This field enables plotting of the
 orbit dots that mark the path of
 the planet as it moves.  The dots
 will only display if the Show Orbits
 setting under the Misc menu is ON.
 Valid values for this field are Y
 and N.

<EDITSTAT>
	   STATIONARY
   This locks the planet firmly in
 place.  New position values are
 not calculated for stationary
 planets.  This is an imaginary
 condition and should not be used
 if you are modeling an actual
 system.

<CONSTZOO>
	      ZOOM POWER
   Changing the zoom power allows you to
 "Zoom-in" and "Zoom-out" to view orbit-
 ing bodies at varying magnifications.
 To zoom-out and see the whole system,
 use small values.  To zoom-in and make
 objects appear very big, use larger
 values.

   This value is also changeable from
 the running simulation by using the
 PgUp, PgDn, and Home keys.

<CONSTXCE>
		X CENTER
   This is effectively a panning value.  You
 enter where in space you would like the
 center of the screen (X direction) to show.

   This value is also changeable from the
 running simulation by using the arrow
 keys in conjunction with PgUp and PgDn.

<CONSTYCE>
		Y CENTER
   This is effectively a panning value.  You
 enter where in space you would like the
 center of the screen (Y direction) to show.

   This value is also changeable from the
 running simulation by using the arrow
 keys in conjunction with PgUp and PgDn.

<CONSTTIM>
	      TIME INTERVAL
   Time Interval is how long a force acts on a
 planet in seconds, or in other words, the
 elapsed time between new velocity and position
 calculations.  The planet motions are simulated
 not by curves, but by many very short lines.
 The time interval relates to the length of those
 lines.  Since in reality they are 0 in length,
 the smaller this number the better.  You may
 lower this number for accuracy, or increase it
 for speed. If the planets are not moving more
 than a few pixels per plot, depending on how
 sharply curved the planet path is, the accuracy
 you are getting is probably fine.  This value
 can be automatically determined with the Dynamic
 Time Interval function ('D' on the simulation
 screen).

<CONSTG  >
	   GRAVITATIONAL CONSTANT
   The gravitational constant is the strength
 of the gravitational field.  You should not
 need to change this value, but it is included
 for versatility.  Changing it will affect the
 units used for mass, density, distance, and
 velocity.  The value of +6.67E-11 is the
 actual value found in reality.

<CONSTCPP>
	  CALCULATIONS PER PLOT
   Actually a bit of a misnomer, this really
 relates to Plots per Calculation.  It only
 affects the frequency of plotting positions
 on the screen, not how the calculations
 are done, or the paths planets will take.
 You may want to change this when you are
 watching the Status Line, or if you have
 very slow display hardware.

<CENTRAL >
	    CENTRAL PLANET TRACKING
   You can watch the simulation from the perspective
 of any one of the defined planets.  This will plot
 the specified planet in the center of the screen
 and the other planets will move in relation to it.
 This does not affect how the calculations for move-
 ment are performed, only how the planets are disp-
 layed.  Using this, you can follow the orbit of one
 system which is part of a larger system.  For
 instance, you can watch the earth-moon system up
 close while it revolves around the sun without
 having to do zoom/pan/zoom/pan/etc.  An entry
 of 0 will turn off this feature.

   This function is also available from the running
 simulation by pressing first the 'C' key, and then
 the key for the planet you want to track
 (1-9, ! @ # $ % ^ &).

<STATUS  >
	      STATUS LINE
   Displays the current status of a planet.  Values
 displayed include: Planet number, Mass, Position,
 and Velocity.  If the planet collides with another,
 the status switches to the live planet.  A value
 of 0 turns this function off.

   This function is also available from the running
 simulation by pressing first the 'S' key, and then
 the key for the planet you want the status displayed
 for (1-9, ! @ # $ % ^ &).

<SAVE    >
		 SAVE FILE
   Enter the full drive, path, and name of the
 file you want to save to.  If you omit the
 path, the current directory is assumed.
 If you omit the extension, .GRV is appended.

<RESTORE >
	       RESTORE FILE
   Enter the full drive, path, and name of the
 file you want to read from.  If you omit
 the path, the current directory is assumed.
 If you omit the extension, .GRV is appended.

<YESNO   >
  Answer with the Y or N key.

<VIDEO   >
	    VIDEO DISPLAY TYPE
   If for some reason your graphics hardware
 is incorrectly detected, you may select
 the proper type to use here.  Also, if
 your monitor supports other resolutions
 than the one detected, you can specify
 the one to use.  Choosing a lower reso-
 lution display may speed up the simu-
 lation.

   This selection can also be specified on
 the command-line when you start the prog-
 ram.  Use the option /? for a list of
 choices.

<END>


