Astronomy Picture of the Day—20180804

Discoverthe cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2018 August 4

CentralLunar Eclipse

ImageCredit & Copyright: Anthony Ayiomamitis (TWAN)

Explanation:Reddened by scattered sunlight, the Moon in the center is passing through the center of Earth's dark umbral shadow in this July 27 lunar eclipse sequence.Left to right the three images are from the start, maximum, and end to 103minutes of totality from the longest lunar eclipse of the 21st century. Thelongest path the Moon can follow through Earth's shadow does cross the shadow'scenter, that's what makes such central lunar eclipses long ones. But July 27was also the date of lunar apogee, and at the most distant part of itselliptical orbit the Moon moves slowest. For the previous lunar eclipse, lastJanuary 31, the Moon was near its orbital perigee. Passing just south of theEarth shadow central axis, totality lasted only 76 minutes. Coming up onJanuary 21, 2019, a third consecutive total lunar eclipse will also be offcenter and find the Moon near perigee. Then totality will be a mere 62 minuteslong.