A Black Moon rises Aug. 23, though you won't see it. Its timing makes it a rare lunar event. On Aug. 23, the night sky will play host to an unusual lunar event known as a Black Moon. While you won't actually see anything unusual (in fact, you won't see the moon at all), this event is still exciting because of its rarity.

A rare black moon is set to occur this week, though night sky observers will not be able to see it. The astral phenomenon is set to leave a moon-sized dark spot in the heavenly panorama on the night of Saturday, Aug. 23.

Saturday's new moon is a seasonal "black moon" — a rare phenomenon that occurs once every 33 months. Here's what that means and why it's a great night for stargazing.