ace (see definition of reference surface in the reference
manual). The <strong>FOB</strong> and <strong>RAY</strong> commands
may also be used to specify that the rays be traced at wavelengths
other than the default control wavelength. You should go to the
reference manual at this point, and read the full descriptions of
the <strong>FOB</strong> and <strong>RAY</strong> commands and also
read about ray aiming. After a ray has been traced, the ray data may
be displayed in a textual sense or plotted in a grap