January 2018 lunar eclipse

January 2018 lunar eclipse

Total eclipse
Totality as viewed from Lomita, California
Date	January 31, 2018
Gamma	−0.3014
Magnitude	1.3155
Saros cycle	124 (49 of 74)
Totality	76 minutes, 4 seconds
Partiality	202 minutes, 44 seconds
Penumbral	317 minutes, 12 seconds
Contacts (UTC) P1 10:51:15 U1 11:48:27 U2 12:51:47 Greatest 13:29:50 U3 14:07:51 U4 15:11:11 P4 16:08:27
← August 2017 July 2018 →

A total lunar eclipse occurred at the Moon’s ascending node of orbit on Wednesday, January 31, 2018,^[1] with an umbral magnitude of 1.3155. A lunar eclipse occurs when the Moon moves into the Earth's shadow, causing the Moon to be darkened. A total lunar eclipse occurs when the Moon's near side entirely passes into the Earth's umbral shadow. Unlike a solar eclipse, which can only be viewed from a relatively small area of the world, a lunar eclipse may be viewed from anywhere on the night side of Earth. A total lunar eclipse can last up to nearly two hours, while a total solar eclipse lasts only a few minutes at any given place, because the Moon's shadow is smaller. Occurring about 1.4 days after perigee (on January 30, 2018, at 4:55 UTC), the Moon's apparent diameter was larger.^[2]

Because the Moon was near its perigee on January 30, it may be described as a "supermoon", when the Moon's distance from the Earth is less than 360,000 km (223,694 miles). The previous supermoon lunar eclipse was on September 28, 2015.^[3] The Moon was 360,202 km (223,819 mi) from the Earth. This eclipse also coincided with a blue moon, which occurs when there are two full moons in the same calendar month, or if there are four full moons in the same season (third of four is blue moon). As this supermoon was also a blue moon (the second full moon in a calendar month), it was referred to as a "super blue blood moon"; "blood" refers to the typical red color of the Moon during a total lunar eclipse. This event was called a 'Trifecta'.^[4] This coincidence last occurred on December 30, 1982 for the eastern hemisphere,^[5] and otherwise before that on March 31, 1866.^[6][7] The next occurrence will be on January 31, 2037, one metonic cycle (19 years) later.