Moon Phase - Waxing & Waning

To tell whether the Moon is waxing or waning is fairly simple. Basically, all you have to do is go outside at sundown and take a look -- if you don;t see the moon then, you will have to go outside later at night and check again, or check during the day:
If the Moon is already up in the sky in the evening, when the Sun goes down, then the Moon is waxing. Every night it will rise a little later in the day and look a little fuller. At Full Moon it will rise almost exactly when the Sun sets.
If the Moon is not already up in the sky when night falls, but instead rises long after sunset, or if you see it faintly during the day, then the Moon is waning. Every day it will rise a little later and look a little thinner. At New Moon it will rise almost exactly when the Sun does, but you won't be able to see it at all.

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Astronomical Applications Department provides a online way to quickly check if the Moon's phase.

You can obtain the times of sunrise, sunset, moonrise, moonset, transits of the Sun and Moon, and the beginning and end of civil twilight, along with information on the Moon's phase by specifying the date and location in one of the two forms.

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