A rare lunar event known as a “Black Moon” will occur this Friday, Sept. 30 at 7:11 p.m. Central time. 

Usually there is just one new moon per month. A Black Moon refers to when there is a second new moon in one month.

According to Nature World News, a new moon is when the earth-facing side of the moon is in full shadow. Basically, a new moon is invisible to the human eye. Because the moon’s dark side is facing us, however, the sky will be extra dark and ideal for stargazing.

Space.com reports that having two new moons in one month only happens roughly every 32 months. The last one we had was in March of 2014. So, Black Moons are kind of a big deal.

Only the western hemisphere can experience this upcoming Black Moon, as it will technically occur in October for the Eastern hemisphere.

Be sure to get a look at the Black Moon this Friday. We won't be able to see another one until to 2019, according to Accuweather.