How to Use a Planisphere (Star Wheel)

The operation is really pretty simple and it should only take everyone a minute or two of practice to get the hang of it. Make the hour of the day line up with the month/day setting and presto, you have your (distorted) sky view on the star wheel.

Ther are are two or three different types of star wheels.

The traditional one has the entire sky on one side. The view is distorted near the southern horizon and constellation shapes are not correct. Even so, scouts should still be able to figure it out after a little practice under the night sky. 

The Chandler planisphere is designed to show all of the sky except the southern horizon on one side, then you flip it over to see the southern horizon. The constellation shapes are preserved which makes it a bit easier to match what you see in the sky. Ten Mile River should have 10-20 of these (though I’m sure there’s been some loss).

Here’s how you can check that scouts know how to use the planisphere. Give a date and time and have the scouts set up the planisphere then name a constellation that appears on the meridian (the middle line between east and west). There will be more than one. Then ask for a constellation near the eastern horizon, then the western horizon. If they’re using them correctly, everyone will agree with the answers. If there’s disagreement, have the scouts help each other to get it right.

Remember, this whole section is supposed to only take 15 minutes.