A very deep penumbral lunar eclipse will take place on February 11, 2017, with the greatest eclipse at 00:45 UTC. It will be visible throughout most of eastern South America, eastern Canada, the Atlantic Ocean, Europe, Africa, and western Asia.
Penumbral eclipses are subtle and hard to observe. They, like other lunar eclipses, occur whenever the Earth passes between the Moon and Sun, such that it obscures the Sun's light and casts a shadow onto the Moon's surface.
About 35% of all eclipses are of the penumbral type which are very difficult to detect, even with a telescope. Another 30% are partial eclipses which are easy to see with the unaided eye. The final 35% or so are total eclipses, and these are quite extraordinary events to behold.
In a penumbral eclipse, the Moon passes through an outer region of the Earth's shadow called the penumbra. This is the outer part of the Earth's shadow, in which the Earth appears to cover part of the Sun's disk, but not all of it.
Credit: NASA/F. Espenak
As a result, the Moon's brightness will begin to dim, as it is less strongly illuminated by the Sun, but the whole of the Sun's disk will remain illuminated to some degree. Although the Moon's light dims considerably during a penumbral eclipse, this is only perceptible to those with very astute vision, or in carefully controlled photographs.
On February 11, the moon will begin to enter the Earth's penumbra at 22:35 UTC. The greatest eclipse will occur at 00:45 and the moon will leave the Earth's penumbra at 02:54 UTC.
This is 4.4 days after the Moon reaches perigee, in the constellation Leo. The synodic month in which the eclipse takes place has a Brown Lunation Number of 1164.
The eclipse belongs to Saros 114 and is number 59 of 71 eclipses in the series. All eclipses in this series occur at the Moon’s ascending node. The Moon moves southward with respect to the node with each succeeding eclipse in the series and gamma decreases.
This is a very deep penumbral eclipse. It has a penumbral eclipse magnitude of 0.9884 and a penumbral eclipse duration of 259.2 minutes. Gamma has a value of -1.0255.
It will be visible throughout most of eastern South America, eastern Canada, the Atlantic Ocean, Europe, Africa, and western Asia.
The penumbral lunar eclipse of February 11, 2017 is followed two weeks later by a annular solar eclipse on February 26, 2017.
Learn more about solar eclipse of February 26 and other celestial events occurring this month in our Night Sky Guide.
Featured image credit: Dominic Ford / InTheSky