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Moon phases

The Moon we see in our sky, white with reflected sunlight, proceeds dependably every 'synodic month' of 29 days through its phases. Because the new moon is almost in line with the Sun and sets at the same time, we see nothing of it. A few nights later, we see the waxing crescent, which many people call the new moon. The waxing Moon climbs higher as it grows rounder. It reaches its first quarter after about a week, sailing high in the sky by sunset, and not setting until about midnight. When it is at its first quarter, we see half of its disc illuminated and half in darkness. The imaginary line between dark and light is called the terminator. It is a good place to look at the Moon with a telescope; the sides of the craters are thrown into high relief by the shadow. The Moon sets later and later as it moves east against the stars. About two weeks after the new moon comes the full moon, rising in the east at sunset and staying in sight all night. During its waning period, the Moon does not rise until late at night. At its last quarter, it rises about midnight, once more showing exactly half of its face in light - the other half this time. Finally, it is new - and invisible - again.

 

 
     
 
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