every circle is divided
into 360 of them. And if you will think a moment, you will understand
why we can see only half the sky at any one time, or 180 degrees,
because the other half of the sky is on the other side of the earth.
Therefore, if you draw a straight line from one horizon, clear up to the
top of the sky and down to the opposite horizon, it is 180 degrees long.
And, of course, it is only half that distance, or 90 degrees, from
horizon to zenith. (Horizon is the point where earth and sky seem to
meet, and zenith is the point straight over your head.)

Now ninety degrees is a mighty big distance in the sky. The Pole star is
nothing like ninety degrees from the Dipper. It is only twenty-five
degrees, or about five times the distance between the Pointers. And now
comes the only thing I will ask you to remember. Look well at the two
Pointers, because the distance between them, five degrees, is the most
convenient "foot rule" for the sky that you will ever find. Most of the
stars you will want to talk about are from two to five times that
distance from some other star that you and your friends are sure of.
Perhaps this is a little hard to understand. If so, read it over several
times, or get some one to explain it to you, for when you grasp it, it
will unlock almost as many pleasures as a key to the store you like the
best.

Now, let's try our new-found ruler. Let us see if it will help us find
the eighth star in the Dipper. That's a famous test of sharp eyes. I
don't want to spoil your pleasure by telling you too soon where it is.
Perhaps you would rather see how sharp your eyes are before reading any
further. But if you can't find the eighth star, I will tell you where to
look.

Look at the second star in the Dipper, counting from the end of the
handle. That is a famous star called Mizar. Now look all around Mizar,
and then, if you can't see a little one near it, try to measure off one
degree. To do this, look at the Pointers and try to measure off about a
fifth of the distance between them. Then look about one degree (or less)
from Mizar, and I am sure you will see the little beauty--its name is
Alcor, which means "the cavalier" or companion. The two are sometimes
called "_the horse and rider_"; another name for Alcor is Saidak, which
means "the test." I shall be very much disappointed if you cannot see
Saidak, because it is not considered a hard test nowadays for sharp
eyes.

Aren't these interesting names