---------------------------------------------------------------------------
   Compute the angle change needed to change the trajectory so that it
   passes through the second right ascension and declination.
---------------------------------------------------------------------------
   Form:
   deltaAngle = DeltaAngleForNewRADec( v1, rA1, dec1, rA2, dec2 )
---------------------------------------------------------------------------

   ------
   Inputs
   ------
   v1         (3,1)   Current velocity vector
   rA1        (1,1)   Current right ascension (rad)
   dec1       (1,1)   Current declination (rad)
   rA2        (1,1)   New right ascension (rad)
   dec2       (1,1)   New declination

   -------
   Outputs
   -------
   deltaAngle (1,1)   Velocity vector angle change (rad)

---------------------------------------------------------------------------