In most years, the 3-hour observing session is done Thursday evening. That means you could wait until Thursday's class to plan it. The problem with that is simple, if it's a bad plan or no plan, the scouts should not be given credit for it. By doing the planning on Wednesday, you give them an opportunity to not only make a plan in advance (which sounds a lot like Be Prepared doens't it?) but you also have the opportunity to comment on their plan and have them correct it. However, there is a possibility that the weather forecast will show that Wednesday night is going to be clear and Thursday not. Note that requirement 8b clearly states "Show your plan, charts, and log or notebook to your counselor before making your observations" (emphasis added). That means they have to have a plan and something that can serve as an observing log, before they go out to the field for that session.
The observing session provides the opportunity to actually check off on requirements 4a-4c and 8b. However, it is very difficult unless you, as the instructor/counselor are fully prepared (mentally as well as administratively).
This session will primarily be for the scouts. I consider it acceptable for scouts to work in groups of 2-3 for planning the session, but each scout must write out their own copy of the plan. Let's face it, the same constellations are going to be visible at the same time for all scouts, so working as a (small) team can help them to teach one another. It also makes it easier to share what may be limited resources (planispheres or star charts). As teams finish their plans, or whenever they think they are finished, they can come to you for approval to execute their plan, i.e., they get permission to participate in the 3-hour observing session (note I did not say "attend," this is their observing session and they are supposed to be keeping a log/journal that night).
To obtain permission, the following should be true.
- The plan must include at least "8 conspicuous stars, 5 of which are magnitude 1 or brighter" (requirement 4b). And they have to be able to show via the planisphere or star chart that those 8 will actually be visible during the 3 hour observing session. If someone lists Betelgueses, Rigel, or Aldebaran (all visible in the winter sky), they get sent back to replan.
- The plan must include "at least 10 constellations, at least four of which are in the zodiac" (requirement 4a). Again, they have to be able to show via the planisphere that those 10 will actually be visible during the 3 hour observing session. If the plan include Taurus, Cancer, or Gemini (all winter zodiac constellations) they get sent back to replan.
- The plan should include the Big Dipper at each of the hour marks (requirement 4c). The Big Dipper is visible year-round from TMR and will be high in the night sky early in the evening.
- The plan should include the Milky Way (requirement 4d, sort of).
- The plan should include a small set of items and when the earliest reasonable time to view it is as well as when the best time to observe it is. This can be crude and you don't have to be very picky about it, but the scouts should be thinking about it. When is the best time to view something? When it's highest in the sky, that is, when it crosses the meridian. When is the earliest reasonable time to view it? Probably about an hour (or two) after it rises. It needs to be high enough about the horizon to be easily seen over any trees that may block the view in that direction.
- They must show that they have something they can use as an observing log/sketch book. They need the log for requirement 8b, they need the sketch book for requirement 4c. It can be the same book/notepad/whatever you think is appropriate.
Technically, the plan doesn't have to include any of those things. The requirements are deliberately vague to allow the counselor lattitude on what is acceptable. Unfortunately, if you're trying to check off on a lot of accomplishments during a single week, the plan does need to include those things. If it doesn't, you won't be able to check off on requirements 4a-4c.