Phases of the Moon

  • We see the Moon (and planets) in the night sky due to reflected sunlight.
  • The Sun always illuminates the side of the object facing the Sun. For a sphere, one half of the object is lit, the other half is dark.

  • How much of the lit side we see depends on our perspective on the object relative to the Sun.

    NOTE!!! All of the sketches below are not to scale. Taken at face value they give you the impression that it is easy for the Earth to block light headed for the Moon or vice versa. In reality the Earth and Moon are tiny and far apart (about 40 Earth diameters). Occasionally you do get an eclipse, but due to the small size of the objects involved compared with their separation eclipses are rare.

    Phases of the Moon  

    New Moon

    Moon lies between the Sun and Earth
    Rises with the Sun and sets with the Sun
    Not Visible
    Solar Eclipse possible

    Waxing Crescent

    Sets an hour or two after the Sun
    Sets about an hour later each night (true for all  phases)
    Visible during most of the day to the East of the Sun
    Darkened portion of Moon illuminated by "Earthshine''

    First Quarter

    Visible until around Midnight
    Visible in the East during daylight in the afternoon
    Rises about Noon

    Waxing Gibbous

    Visible almost all night
    Sets just before dawn
    Rises in the East shortly before Sunset

    Full Moon

    Rises just as the Sun sets
    Visible all night.  Not visible during the day.
    Sets at Sunrise
    Lunar Eclipse possible.

    Waning Gibbous

    Rises an hour or two after Sunset
    Visible most of the night
    Visible for a few hours after Sunrise in the West

    Last Quarter

    Rises about Midnight
    Visible the rest of the night
    High in the sky at Sunrise
    Visible in the daytime until Noon

    Waning Crescent

    Rises in the East just before dawn
    Sun rises an hour or two later
    Rises about an hour later each day (true for all phases)
    Darkened portion of Moon illuminated by "Earthshine''

    New Moon...

     

  • To figure out rising and setting times for yourself consult this diagram.