Could you please teach me the interpretation and meaning of the sentence plainly and in detail?: ...you don't want observing to subtract intelligence. I think the possibility of the interpretation is the following:

(1) You don't need to be observed to reduce your intelligence.
(2) You don't hope that you are observed to reduce your intelligence.

In addition, the sentence in question is contained in the following context:

, gather some items beyond your scope, eyepieces, and star atlases. Memories of my high school days, when I used to routinely stay up all night observing, suggest several factors that help one push on through the night. First, bring a number of snacks and drinks that will keep your blood sugar level relatively high. Dissolving those carbs into the bloodstream helps maintain your alertness. Second, take a radio along. Music or all-night talk shows also help maintain a mental focus. Avoid taped reruns of Rush Limbaugh, though - you don't want observing to subtract intelligence. And stay relatively active. By that I mean check charts, adjust the knobs on the radio, and so on. You can be only so active standing or sitting about and looking through a scope, but if you get too relaxed the sleep hormones will win. With that in mind, get ready to set off on an adventure through some familiar and some new and strange galaxies. By midnight Lyra and Hercules stand overhead and the Milky Way arches from Cassiopeia in the