DENVER, Colo. - There's an unusual concurrence of lunar phenomena tonight, with the convergence of a Supermoon, new moon and so-called Black Moon.

Supermoons are also known as perigee moons. Perigee means “near Earth.” The term Supermoon was coined by astronomer Richard Nolle, who defined them as “a new or full moon at or near (within 224,834 miles of Earth) of its closest approach to Earth.

We will have six Supermoons in 2015: the new moons of January, February and March, and the full moons of July, August and September.  The closest full Supermoon will be in September and tonight will be the closest new moon Supermoon.

Tonight’s new moon will be the second Supermoon of 2015.  However, you won't be able to see it. On the day of a new moon, the moon is aligned more or less exactly between the sun and Earth. We can’t see it because it follows the sun, rising and setting when the sun does. In addition, the new moon’s lighted hemisphere is facing away from us.  A day or two later the moon will reappear in the west after sunset. Then it’s a young moon, a slender crescent visible only briefly after sunset.

Because tonight’s new moon is the third of four new moons in the winter season (December solstice to March equinox), it is also a seasonal Black Moon. So tonight we will have a new moon Supermoon Black Moon!

The next February Black Moon will not occur until 2018.