The sky will be illuminated by a double lunar phenomenon on the night of Tuesday to Sunday: the Harvest Supermoon and a partial lunar eclipse.

Supermoons are full moons that appear larger because they occur at the same time as the Moon’s orbit is closest to Earth.

According to NASA, this means the moon will appear 30% brighter and 14% larger than when it is at its dimmest.

Tuesday’s supermoon is also called the Harvest Supermoon because it is the full moon that appears closest to the autumn equinox. The name goes back hundreds of years, when farmers sometimes used the moonlight to work later in the evening.

But the bright sky is not the only sight that can catch the viewer’s eye.

The full moon – the second in four consecutive months of supermoons – coincides with a partial lunar eclipse, which occurs when the Earth passes between the sun and the moon, casting a shadow on the moon.

In this case, about 3.5% of the Moon appears obscured by the Earth’s umbra, a term used to describe the darkest part of the Earth’s shadow.

Unlike the solar eclipse in April, no special glasses are required to safely observe this eclipse.

In Southern California, the moon will rise at 6:52 p.m. The moon’s greatest brightness will appear at 7:44 p.m. and gradually fade over 31 minutes. The moon will be brightest at 9:48 p.m.

Tuesday’s moon follows the super blue moon of August 19. The term does not describe the color of the moon, but refers to the second full moon in a calendar month.

Experts assume that supermoons are moons that are 90% of the distance from the Earth’s closest orbit.

August’s supermoon was about 360,000 kilometers from Earth. This month’s supermoon is a little closer: 367,000 kilometers.

The next supermoons are on October 17 and November 15.