Due to the earth’s rotation, stars appear to move.  As the Earth rotates from west to east, the stars appear to rise in the East, moving across south to set in the west.  The Sun will appear to move through the stars, making one complete circuit of the sky in 365 days.

Stars form patterns in the sky and are referred to as constellations.  It is these patterns that the ancient Greeks used to tell stories of mythology and their gods.  There are 88 constellations that make up the sky.

  The earth is tilted 23.5 degrees off the vertical.  This not only gives us the seasons but also changes which constellations we see.  Those constellations that we can see year round are called circumpolar.  These constellations all circle the North Star and because we live in the Northern Hemisphere, we see them all year round.  These constellations are: Ursa Major, Cassiopeia, Ursa Minor, and Cygnus the Swan.



Yearthe time it takes for a planet to go all the way around the Sun ex:  on Earth a year is 365 days.

Axis: a straight line that an object or body rotates, or seems to rotate around.

Annual Motion: the Earth’s orbital motion around the Sun every year.

Rotation: the motion of a planet, satellite or the Sun around its north-south axis.  It takes 24 hours for the Earth to rotate once on its axis.

Equator: an imaginary circle around the center of the Earth, perpendicular to the axis of rotation.



1. What is the imaginary straight line that an object seems to rotate around?

2. What is the motion in which a planet or satellite moves around another celestial object?

3.  What is the imaginary line that circles the center of the Earth?

4.Tell two new pieces of info that you learned from the links provided concerning this topic. Insert these into your defense log.




(Pause on hover buttons for answers)

  1)                       2)          3)




      Constellation Photos

   A Constellation Primer

     Following the Drinking Gourd

      Astronomical Information