A fall harvest supermoon put on a rare celestial show Tuesday when it also created a partial lunar eclipse for skygazers around the world. The bright harvest supermoon — a full moon that happens around the autumnal equinox — entered Earth’s shadow around 10:13 p.

If you happened to notice the supermoon looking especially large as it was rising, you may have fallen victim to a “well-known, poorly studied optical illusion,” said NASA’s Noah Petro. Here’s the scientific explanation of what you were seeing,

Not only is September's full moon also a so-called "supermoon" because of its size and brightness, but it's also due to be eclipsed by Earth.