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This Sunday night moon observers have the chance to see a lunar triple treat, weather permitting.

First, the moon will be full, as it always must be for a lunar eclipse to occur. This is a special full moon, because this is the Harvest Moon. Because the angle of the ecliptic —the path the moon and planets follow across the sky —is low to the horizon, the moon rises about the same time every night, giving farmers an extra supply of light when they most need it, at harvest time.

Second, the full moon will be at its closest to Earth in all of 2015, what is known to astronomers as a "perigee moon." In recent years this has become known as a "supermoon." Perigee (meaning "closest to Earth") occurs at 10 p.m. EDT, the moon being a mere 222,374 miles (357,877 km) from Earth.