Navigating the Night Sky

Navigating the Night Sky: Script (30-40 minutes)

Set-Up

Latitude: Home
Precession: Current
Set Sun and sky for today's date
Time: About 9:00 pm
Turn off Sun, Moon, planets, NESW lights
Current star map for each member of the audience
Laser pointer
Lights up

Dialog is in normal type, actions/audience parts are in bold italics and indented.

Note: the following script is not meant to be followed word-by-word; rather, use it as a guide. Embellish it, change it, whatever you feel most comfortable with. We do suggest, however, that you involve your audience as much as possible. Have them predict results, explain results, use the laser pointer, make comments, ask questions. A good way to get questions: "Before we conclude this program, I need to hear 5 questions about the night sky."

Getting Acquainted

Good morning (or afternoon)!

Ensure an enthusiastic response.

Introduce yourself. Remind audience that there should be no eating or drinking in the planetarium. Have them put their packs, coats, etc. under their seats.
Humorously: How many here (because we live in the Northwest where it seem to rain all the time) have actually seen the stars?

Show of hands.

How many here have been camping away from the bright city lights and noticed that there are many more stars in the sky?

Show of hands.

How many stars to you think you saw?

Take any number. The actual number of individual stars visible to the naked eye is about 6000. Of course, thousands and thousands more become visible just with the use of binoculars.

I am going to slowly turn down the lights in here. The stars that you will be seeing in just a few moments are just as they will appear tonight in our sky. Imagine that you are home, the Sun is setting, and it is getting dark outside.

Slowly turn down the dome lights as you are talking. For the youngest children it is best to let them know that it will be getting dark and assure them that you and their teachers are not going anywhere!

You all know that when you go from a bright area to a dark area that it takes your eyes a little while to adapt. Keep looking at the planetarium sky and as your eyes adjust, see if you can see patterns of stars that look like a shapes that you know. These familiar patterns of stars in the sky are called "constellations."

Give the students time to find their pattern. It does not need to be an actual constellation. Most likely, the asterism that forms the "Big Dipper" will be the first recognized.

Very good! The pattern of stars that we call the Big Dipper is actually part of the constellation known as the "Great Bear" or Ursa Major. Who knows another name for the Big Dipper? Constellations have always been important for finding directions. The slaves used the Big Dipper, or the Drinking Gourd to help them keep traveling north to freedom. Today sailors, flyers, and even astronauts tell directions by the stars.

Let's pretend that you are lost in a big open field. You know that there is a freeway to the North, with a gas station and a telephone where you can call home. How do you find which direction is North?

Wait for responses. Usually someone knows, no matter how young the crowd. Once you have a volunteer, give HIM OR HER the laser pointer and let him/her point out how to find the North Star

In any event, use your pointer to show how to use the "pointer stars" to step to Polaris, then to the northern horizon. Ask for a volunteer to come to the center and face North. As the student holds out her/his right arm, have audience identify East, then South, then West as the student holds out her/his left arm.

Turn on NESW lights.

Astronomers, the men and women and boys and girls, who study the universe use constellations as convenient location markers to find and name interesting objects, like the "great galaxy in Andromeda."

Every civilization, all over the Earth, has names and stories about the stars and about the patterns that these stars form. People who lived at different times, in different places, often chose the same groups of stars as constellations, but imagined them to look like the particular animals or other objects that were important in their culture. For example, we've learned that the Big Dipper is also known as the Great Bear and the Drinking Gourd. But, did you know it has also been seen as a Cart? And, in Native American lore, it was the seven brothers. If you look very closely, the star that is right in the crook of the handle is really two stars. The tiny, dim star is the little sister. Constellations are names for patterns found in the stars by humans. Just as we have names for our states where cities and towns are located, astronomers name the constellations so that they can find the various stars and other objects that are located there. Astronomers have extended the number of constellations in the sky from the original 44 to 88! Every bit of the sky belongs to a constellation.

Reading a Star Map
INTRODUCTORY EXERCISE: This next exercise will take at least 10 - 15 minutes, as the audience will really get involved. Make sure there is time for each person to locate his or her constellation.
Just as past cultures named the patterns of stars after objects and stories that were important to them, we can make up our own patterns of the stars and have those patterns represent today's culture. My next request is for each of you to find your very own constellation.

Give the audience time to study the stars and pick out their constellation. Emphasize it won't matter if different students choose the same pattern of stars. You may wish to have the students work in groups of two or three.

Turn up reading lights (or twilight). Pass out the star maps, one to each participant, for a more conventional method of locating stars and constellations. This may also be done as the audience is entering the planetarium. The best star maps are those contained in the center fold of Mercury magazine.

These are maps of the sky which we will use to identify some of the major constellations that can easily be seen this month. After you have some experience using these maps here in the planetarium, your map will be yours to take home so that you can identify constellations from your own backyard. These maps can be used for the next few weeks. Notice that the whole sky visible to us is compressed on these charts to fit within a circle. The dots on the map represent stars--the bigger the dot, the brighter the star will be. Only the very brightest stars are shown here. Why don't we show all of the stars in the sky?

Wait for answers. Because there are too many!

What do you think the edge of the big circle on the map represents? It's the horizon: where the Earth seems to meet the sky and what you see when you look straight out horizontally.

Point out, indicating the planetarium horizon. Point out the norther horizon (N), eastern horizon (E), etc.

If a star is near N (for example), it will be near the northern horizon. Point to the very center of your star map. Now point to where that center point is in the planetarium sky. Directly overhead, you're right!

One key to using this star map is in how you hold it. If the star or constellation you are looking for is closest to the northern horizon, you must hold the map so that "northern horizon" or "N" is at the bottom. That way, the stars in that part of the sky will be right side up on your map. If you are looking for stars in the southern part of the sky, turn the map so that "southern horizon" or "S" is at the bottom and the stars in the south will l ook right side up on your map.

As an example, let's use the map to find Cassiopeia, the queen. When you find Cassiopeia, raise your hand. If you have trouble, ask your neighbor for help.

When most students indicate they have found it, go on.

Which direction should you fact to find it? Is Cassiopeia near the h orizon or high up in the sky?

Make sure everyone agrees before going on

Now watch me as I use the map to find Cassiopeia in the sky. On the map, Cassiopeia is closest to the northern horizon so I know I should face North and hold this map so the words "northern horizon" or "N" are at the bottom. When I look at the sky, about this high, I should see the same pattern of stars that appears on the map, and there it is! If I were looking for a constellation in the South, let's say Aquarius or Canis Major, I would turn the map so that the words "southern horizon" or "S" are at the bottom.

Keep in mind the 6-step recipe for finding constellations:

locate the constellation on the map
describe the pattern to yourself
determine what direction you must face
turn the map so that direction is at the bottom
decide if your constellation is high in the sky or near the horizon
compare your map with the stars you see in the sky.
Let's practice again with Ursa Minor, or the little bear.

Have the students repeat each step as they follow the recipe.

Concluding activity for younger audiences: a constellation to take home.

Just like past cultures, we can find patterns in the sky that relate to what we know today. Now, I'd like to have groups of you find your own, personal constellations.

Turn up the planetarium side lights slightly. Pass out pencils and white sheets of paper. Ask each person to "sketch" their constellation by marking a series of dots on their paper. They can then "connect the dots" for their constellation picture.

Have each person display their constellation, give their made-up name for it, and use the laser pointer to point it out in the sky. Discuss the variety of answers and the good job each group did. (Exercise adapted from "Create a Constellation" by Dennis Schatz, Pacific Science Center.)