A new moon is the moment the moon passes between the Earth and the sun, its lit side turned away; it rises and sets with the sun, unseen.

The new moon is the start of the lunation, day zero of the moon's age. The first crescent shows a day or two later, low in the west after sunset, and grows toward the east each evening. If the moon crosses exactly between, its shadow falls on the Earth and that is a solar eclipse.

The darkest nights of the month follow, which is when the stars and the Milky Way are best.