The longest total lunar eclipse of the 21st century is just a month away.
The total phase of the "blood moon" eclipse of July 27 will last 1 hour and 43 minutes, during which Earth's natural satellite will turn a spectacular red or ruddy-brown color. From start to finish, the entire celestial event will last nearly 4 hours.
The eclipse won't be visible to viewers in North America, except via webcasts. But observers in much of Africa, the Middle East, southern Asia and the Indian Ocean region will get an eyeful, given cooperative weather, according to lunar scientist Noah Petro, of NASA's Goddard Space Flight Center in Greenbelt, Maryland. [In Photos: The Rare Super Blue Blood Moon Eclipse of 2018]
What is the Blood Moon of July 27?
Unlike with solar eclipses, you need no special equipment to observe lunar eclipses. These latter events, which occur when the moon passes into Earth's shadow, are safe to view directly with the naked eye, telescopes or binoculars.
The moon turns deep red or reddish brown during eclipses, instead of going completely dark. That's because some of the sunlight going through Earth's atmosphere is bent around the edge of our planet and falls onto the moon's surface. Earth's air also scatters more shorter-wavelength light (in colors such as green or blue); what's left is the longer-wavelength, redder end of the spectrum.
Where and when will it be visible?
The timing if this total lunar eclipse means it won't be visible from North America, though much of the Eastern Hemisphere of Earth will see part or all of the eclipse. The entire eclipse will be visible from Africa, the Middle East and countries in central Asia. The eclipse will be visible from eastern South America as it is ending, and from Australia as it is beginning.
The time of greatest eclipse will be 4:21 p.m. EDT (2021 GMT) on July 27.The total eclipse will last from 3:30 p.m. to 5:13 p.m. EDT (1930 to 2113 GMT). There will also be some time before and after when the moon is in the lighter part of Earth's shadow, which is called the penumbra. Including that penumbral time, the eclipse will last for 3 hours and 55 minutes.
The time of greatest eclipse will be 4:21 p.m. EDT (2021 GMT) on July 27.The total eclipse will last from 3:30 p.m. to 5:13 p.m. EDT (1930 to 2113 GMT). There will also be some time before and after when the moon is in the lighter part of Earth's shadow, which is called the penumbra. Including that penumbral time, the eclipse will last for 3 hours and 55 minutes.
Why is it the longest of the century?
Additionally, the moon will be at a farther point from Earth along its orbit, EarthSky pointed out. That means the moon will appear slightly smaller in the sky and will take a little bit longer to go through Earth's shadow.
Petro is the project scientist for NASA's Lunar Reconnaissance Orbiter(LRO), which has been orbiting the moon for nine years. It is best-known for obtaining detailed information on water ice and taking high-resolution pictures of spacecraft on the lunar surface. Because LRO is an older probe, most of its components (except for battery warmers and the like) will be turned off during the eclipse, to preserve the solar-powered spacecraft's battery and keep it safe during the greatest part of the eclipse, Petro said.