The Moon

Visible phase determained by:

1. Current phase

2. Position of the sun in the sky (time)
3. Position of the moon in the sky

At sunset: full is rising, first quarter is high in the sky, new is setting (third quarter sets at noon)

Moon is offset from Earth Sun by .5*

Orbital plane of moon around earth is different than that of the earth around the sun

Only solar eclipse when phase is new

penumbra = outershadow of moon (only part of the solar eclipse)

umbral shadow = inner shadow of moon (full eclipse) about 300km on earth at a time and never longer than 7 minutes

annular eclipse (when moon doesn’t completely cover the solar disk), umbral shadow is not complete

Lunar eclipse is longer (earth is bigger)

1. Takes hours
2. Penubral shadow has almost no effect
3. At totality, it looks red due to refraction through earth’s atmosphere