
and <strong>SCW</strong> at the CMD level, issue the following two
commands:</p>

<p><strong>
    PCW ?<br>
    SCW ?<br>
</strong></p>

<p>To calculate the primary chromatic differences for 3<sup>rd</sup>,
5<sup>th</sup>, and 7<sup>th</sup> order spherical aberrations, issue
the command:</p>

<p><strong>PCDSA ALL</strong></p>

<p>Try the other primary and secondary chromatic difference commands
described in the CMD section.</p>

<h2>Lesson #5 - Tracing Individual Real Rays</h2>

<p>Individual real trigono