This document discusses the history and uses of constellations. It explains that constellations have traditionally been used for navigation, such as by escaped slaves using the Big Dipper and North Star to travel along the Underground Railroad to Canada. The document also notes that the North Star is unique among stars as it does not appear to move in the night sky. Finally, it provides instructions for building a simple astrolabe or sextant to measure the positions of stars.

1. Sunday, September 7th
, 2008
SPACE
Constellations
Part II

2.  Today there are 88
commonly accepted
constellations by star
watchers around the
world.
 animation

3.  Traditionally,
constellations were used
to find directions (using
an astrolabe seen here)
 They were even used by
escaped slaves on the
Underground Railroad
trying to find their way to
Canada.
 They looked for the
pointer stars in the big
dipper to find the North
Star because they knew if
they went North they
would eventually get to
Canada and safety.

4.  They called the big
dipper the “Drinking
Gourd” and sang a
song with secret code
words in it to
remember where to
go.
 Hear the song

6. DID YOU KNOW!
 The North Star (Polaris)
is the only star in the
night sky that doesn’t
move!
 The earth rotates under
this spot making it appear
as if all of the other stars
rotate around it.
 That’s why it’s the only
one that will lead you in
the same direction at all
times.

7.  Another
constellation that
is easy to find is
Casseopeia.
 To find her, use
use the pointers
to find polaris
and then keep
going toward the
other side of the
sky.
One Last One!

8. Build Your Own Sextant or Astrolabe!
 Look through the straw
at a star and measure
the angle of the string
on the protractor.
 Wait one hour and re-
measure the same star
and see if the angle
changed.

9. Homework
 Find Orion or the Big Dipper in the sky
tonight.
 Use your homemade sextant to look at it
at 7:00 and then at 8:00 – was it at the
same degree each time ?

10. Just For Fun!
 Constellation Hunt!