A total lunar eclipse is happening on July 27 to 28, and it’s about to be the longest one that people in the 21st century will see in their lifetime.

The “blood moon” eclipse will have its total phase last an hour and 43 minutes on July 27, a time when Earth’s satellite will be displayed in such a glorious red or ruddy brown color. The anticipated celestial event will last almost four hours.

What’s The Blood Moon?

The moon becomes deep red or reddish brown in color during an eclipse, not completely dark, as some of the sunlight passing through the planet’s atmosphere is bent around the Earth’s edge and falls onto the lunar surface.

After Earth’s air scatters more of shorter-wavelength light, such as in green or blue hues, what's left are the longer-wavelength ones, which are at the redder end of the spectrum.

The total eclipse in July will showcase all the bright colors expected of a blood moon, appearing either in deep red or orange. There will also be Rayleigh scattering, removing green and violet light particles in the sky during the eclipse.

What Makes It So Special?

Typically, there are two lunar eclipses each year, although not all of them are total eclipses. This particular lunar eclipse is very long due to the day it falls on.

Depending on one’s location in the world, July 27 to 28 will mark both a full moon and a moon apogee. The latter is the farthest orbital point from Earth and combined with a full moon it will lead to the extended eclipse.

“This smaller and slower-moving full moon takes more time to cross the Earth’s shadow than does a full moon that’s closer to Earth and moving faster in orbit,” said astronomer Bruce McClure of Earthsky.

When And Where To See The Eclipse

The total eclipse will occur from 3:30 p.m. EDT until 5:13 p.m. EDT. The moon will be partially eclipsed for about an hour before and after the eclipse, while the maximum eclipse will happen at 4:21 p.m. EDT. Given this timing, the eclipse won’t be visible from North America.

Instead, the entire eclipse will be visible over Eastern Africa and Central Asia, and partially seen over Western Africa, Eastern Asia, South America, Europe, as well as Australia.

As a bonus, Mars will also appear especially large and bright in the sky, as the planet moves toward its closest approach to Earth in 15 years’ time. Skywatchers may then be able to catch a glimpse of the red planet along with the spectacular blood moon.

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