(The next similar total lunar eclipse visible to us will be on 07th September, 2025)
The longest total lunar eclipse of the 21st century will be visible to Sri Lanka on 27th July 2018 starting from 10:44 pm onwards. A lunar eclipse occurs when the moon passes through the shadow of the Earth. Being an extended light source the Sun casts the shadow of the earth onto earth’s atmosphere and onto the space with two parts, namely Umbra and Penumbra. A total lunar eclipse occurs when the entire moon passes through the Earth’s umbra. A partial lunar eclipse happens when a portion of the moon traverses the umbra. A penumbral lunar eclipse occurs when the Moon passes through Earth’s penumbra.
The orbit of the moon around the earth is an eclipse and when the moon is near the apogee, the farthest point of its orbit from the earth, the speed of the moon is the slowest. During 27th July, 2018 eclipse the moon will be very close to apogee. Therefore, moon will take long duration to travel through the earth shadow and make this eclipse the longest in the century.
The totality of the eclipse will last for 1 hour and 43 minutes, take 03 hours and 54 minutes for umbral eclipse and 06 hours and 13 minutes for penumbral eclipse.
|Timings of the eclipse for Sri Lanka
P1 = 22: 44:49
U1 = 23:54:27
U2 = 01:00:15
Greatest = 01:52:54
U3 = 02:43:12
U4 = 03:49:00
P4 = 04:58:37
Penumbral = 06h13m48s
Umbra l =03h54m32s
Brightness and Color of Total Lunar Eclipses
The brightness and the color of a total lunar eclipse vary a lot from eclipse to eclipse depending on the amount of dust, water and other particles present in the earth atmosphere, during the time of the eclipse. These constituents reduce the amount of sunlight and filter out some colors in the sun light going in to the shadow of the earth. This makes a total lunar eclipse appearing in different brightness (nearly invisible) and colors such as hues of orange, through deep red, dark brown or dark grey.
The following scheme introduced by a French astronomer Andre-Louis Danjon, is used to determine the brightness of a total lunar eclipse.
One can assign a ‘L’ value to a lunar eclipse observing its totality by naked eye or a small telescope.
Why not capture this spectacular lunar eclipse on your camera!