1. Moon Who is this guy? Use SkyGazer or StarCal to find out!
Retrograde motion of Mars, June to November, 2003
Who is this guy?
Use SkyGazer or StarCal to find out!

2. The Moon Facts about the Moon…
We see the moon changes its appearances and position in the sky with approximately 30-day cycle.
Unlike the stars, Moon can also be seen during the day.
We also see that the Moon is always involved in eclipses, and
Its position seems to be well correlated with the tide of the ocean.
Understanding the motion of the Moon with respect to the Sun and the Earth will explain these phenomena.
The moon revolves around the earth with a period of about 29 ½ days ~ one month!

3. Motions of the Sun-Moon-Earth System
Earth orbits the Sun every 365 ¼ days
Moon orbits Earth every 29 ½ days
Click on the image to start animation:
This is what the orbit of the Moon looks like…
The orbit of the Moon around Earth is tilted about 18.5 degrees with repect to the ecliptic plane
Moon’s orbit around Earth precesses with a period of 18.5 years
Click on the image to start animation

4. The changing phase of the Moon… The un-changing face of the Moon…
Eclipses
Lunar Eclipse
Solar Eclipse

5. The Face and Phases of the Moon
The phase (how much and which side of the Moon is illuminated) of the Moon changes with about one month period…
The face (the features on the surface of the Moon) does not change at all…

6. The Phase of the Moon
The phase of the Moon depends on the relative position between the Sun, the Earth, and the Moon…

7. Phases of the Moon Click on the image to start animation
You can use this tool from the Phases of the Moon tutorial to present the idea behind phases in another way. As usual, please encourage your students to try the tutorial for themselves.
Click on the image to start animation

8. Moon Rise/Set by Phase
Click on the image to start animation

9. Why do we Always See the Same Side of the Moon?
The rotation period of the Moon with respect to the universe is exactly the same as the rotation period of the Moon around the Earth.
Is this a coincidence?
No!  Tidal Lock, Chapter 5.

10. Seasons, moon, eclipses, tides