Weather permitting, sky gazers in northern America and Europe are in for a treat in the early morning hours of Tuesday, when the first total lunar eclipse in almost three years is poised to turn the Moon pink, coppery or even a blood red.
Coinciding eerily with the northern hemisphere’s mid-winter solstice, the eclipse will happen because the Sun, the Earth and its satellite are directly aligned, and the Moon swings into the cone of shadow cast by its mother planet.
The Moon does not become invisible, though, as there is still residual light that is deflected towards it by our atmosphere.
Most of this refracted light is in the red part of the spectrum and as a result the Moon, seen from Earth, turns a reddish, coppery or orange hue, sometimes even brownish.
The eclipse runs for three and a half hours, from 12:30 a.m. to 4:01 a.m., although the stage of total eclipse — when the Moon heads into the “umbra” cast by the Earth — lasts from 1:41 a.m. to 02:53 a.m.
The last total lunar eclipse took place on February 21 2008. Next year, says Espenak, will see two: on June 15 and December 10.
A solar eclipse happens when the Moon swings between the Earth and the Sun.