Super Harvest Moon, partial lunar eclipse to combine for rare celestial trifecta

Sept. 16 (UPI) -- A Super Harvest Moon with a partial lunar eclipse will light up September's night skies Tuesday in a rare celestial trifecta as summer begins to wind down.

The partial eclipse , that will begin late Tuesday night and run into Wednesday morning, will occur during the Supermoon -- when the moon's orbit is slightly closer to Earth -- and will be visible from most of North and South America, Europe, Africa, western Asia and parts of Antarctica.

A Supermoon, which is the largest and brightest moon of the year, is a full moon that occurs when it is within 90% of its closest orbit to Earth. In this case, it is also called a "harvest moon" because Tuesday's full moon is the closest to Sunday's autumnal equinox, when summer officially ends.

Lunar eclipses occur when the sun, Earth and moon line up with the Earth casting its shadow on the moon, making it appear darkened and reddish. Tuesday's partial lunar eclipse will shadow a small 8.7% sliver of the moon.

Those parts of the world that will not be able to see the rare lunar trifecta, and areas where weather impedes visibility, will be able to watch livestreams online for free.

TimeAndDate.com will host a livestream of the partial lunar eclipse, starting Tuesday at 9 p.m. EDT. And Adler Planetarium in Chicago will host a lunar eclipse livestream starting at 10 p.m. EDT, featuring astronomers and live commentary.

The full moon will reach its peak in the United States on Tuesday at 10:35 p.m. EDT, according to NASA. The moon will appear full for about three days, through Thursday morning.

The partial lunar eclipse will enter Earth's shadow starting at 8:41 p.m. EDT on Tuesday and will peak at 10:44 p.m. with only the top 8.7% of the moon in full shadow. The partial eclipse is expected to wrap up early Wednesday morning at 12:47 a.m.