Update FAQ.html: Better explain how to focus

html/documentation/miscellaneous/FAQ.html

@@ -252,16 +252,21 @@ <h2>How do I focus my allsky camera?</h2>
 Try get your camera at least roughly focused during the day.
 It'll be easier to see the focus ring on your lens,
 and exposure duration will be much shorter so you'll get more instant feedback.
+Focusing on slow-moving clouds works well.
 </p>
 <p>
-To complete focus, enable the <span class="WebUISetting">Show Focus Metric</span>
+Enable the <span class="WebUISetting">Show Focus Metric</span>
 setting in the WebUI's <span class="WebUIWebPage">Allsky Settings</span> page.
 A focus number will appear on your images - the higher the number, the better focus you have.
 Note that the number can change depending on the brightness,
 so focus when the brightness isn't changing.
 <p>
 When done focusing, disable the <span class="WebUISetting">Show Focus Metric</span>
 setting since it's no longer needed.
+While this method may be "good enough", the most accurate way to focus is
+at night using stars.
+Zoom in on the image and look for stars that are bright but not saturated.
+Keep focusing until the stars are as small as possible.
 </p>
 </details>