Rare ‘black moon’ rises over Western Hemisphere Friday night

In this Jan. 9, 2008, file photo, one day past New, an early Waxing Crescent Moon is seen just after sunset from Tyler, Texas. A rare "black moon" rises over the Western Hemisphere on Friday, Sept. 30, 2016. A black moon is the second new moon in a calendar month. (AP Photo/Dr. Scott M. Lieberman, File)

PHILADELPHIA (AP) — A rare “black moon” rises Friday night over the Western Hemisphere, but don’t expect to see it.

NASA says a black moon is the second new moon in a calendar month. A new moon is the start of the lunar cycle and the phase where the moon is impossible to see because it’s completely shrouded in darkness.

A black moon occurs about once every 32 months. Friday night’s officially takes place at 8:11 p.m. on the East Coast.

The term “black moon” contrasts with “blue moon,” which is the second full moon in a calendar month.