A Solar eclipse, equinox, and a supermoon all occur on the same day.

A total solar eclipse occurred at the Moon's descending node of orbit on Friday, March 20, 2015, with a magnitude of 1.0445. A solar eclipse occurs when the Moon passes between Earth and the Sun, thereby totally or partly obscuring the image of the Sun for a viewer on Earth. A total solar eclipse occurs when the Moon's apparent diameter is larger than the Sun's, blocking all direct sunlight, turning day into darkness. Totality occurs in a narrow path across Earth's surface, with a partial solar eclipse visible over a surrounding region thousands of kilometres wide. Occurring about 14 hours after perigee, the Moon's apparent diameter was larger.

A solar equinox is a moment in time when the Sun appears directly above the equator, rather than to its north or south. On the day of the equinox, the Sun appears to rise directly east and set directly west. This occurs twice each year, around 20 March and 23 September.

A supermoon is a full moon or a new moon that nearly coincides with perigee—the closest that the Moon comes to the Earth in its orbit—resulting in a slightly larger-than-usual apparent size of the lunar disk as viewed from Earth. The technical name is a perigee syzygy or a full Moon around perigee. Because the term supermoon is astrological in origin, it has no precise astronomical definition.