paraxial marginal ray height (PY),
paraxial marginal ray slope tangent (PUY), paraxial chief ray height
(PCY) and paraxial chief ray slope tangent (PUCY) will be
generated. The output is always calculated at the current control
wavelength. Look up and read about the <strong>PXTY</strong>
command. Try the other paraxial ray output commands described in the
same section. The commands are in the CMD section of the reference
manual. Try the single surface modes of these commands, like:</p>

<p><strong>PXTY 3</s