A total lunar eclipse is due to occur at the end of this week, and it should be visible across much of the United States for those with clear skies. The eclipse will start on Sunday night, May 15, and last until Monday morning.
There are different types of lunar eclipse: a total one, in which the entire moon falls within the darkest part of the Earth's shadow; and a partial one, in which the moon is only partly obscured.
A lunar eclipse takes place when the Earth comes between the sun and moon. Lunar eclipses tend to make the moon appear reddish-brown in the sky because although the Earth is blocking the sun's light from reaching the moon directly, some of its light is scattered through the Earth's atmosphere and reaches the moon that way. This is why lunar eclipses are sometimes given the eerie-sounding but scientifically explainable name "blood moons."
Light scattered through the Earth's atmosphere appears red in color, which is the same reason sunrises and sunsets have their picturesque glow.
A lunar eclipse is not the same as a solar eclipse, in which the moon moves between the sun and the Earth and blocks out the sun temporarily. It is never safe to look directly at the sun without a safe solar filter, even if the sun is partly or mostly obscured. Solar eclipses must be viewed with solar viewing or eclipse glasses. These are not the same as regular sunglasses, which are not safe for viewing the sun.
Unlike solar eclipses, no special equipment is required to view a lunar eclipse although binoculars or a telescope can help. Clear skies and a dark environment away from light pollution will create the best viewing conditions.
There will be a full lunar eclipse this weekend that should be visible throughout much of the U.S. with clear skies. Sunlight scattered through the Earth's atmosphere causes the moon to appear red during lunar...There will be a full lunar eclipse this weekend that should be visible throughout much of the U.S. with clear skies. Sunlight scattered through the Earth's atmosphere causes the moon to appear red during lunar eclipses.Petr Svoboda/GettyThe moon will begin entering Earth's shadow at around 9:32 p.m. ET on Sunday, though this may not become noticeable for an hour or so according to a NASA blog post by Gordon Johnston, a former program executive for the space agency who now writes about regular skywatching opportunities.
"The slight darkening of the moon will not stand out until the moon enters the Earth's full shadow," Johnston said.
The eclipse will reach its peak at around 12:11 a.m. ET on Monday morning—be sure to check how this translates to other time zones across the U.S. if you are not in the Eastern time zone—and will totally exit Earth's shadow at around 2:51 a.m.
The eclipse will be best viewed from the eastern half of the U.S. and all of South America where people will be able to see every stage of it. In central and western parts of the country, it may only be possible to see part of the eclipse. An animation showing how the eclipse will evolve over time and where it will be visible can be seen on the time and astronomy website Time And Date here.
For those who won't be able to catch it, NASA will host a live stream here from 11:00 p.m. to 12:00 a.m. ET on Sunday, May 15.
This eclipse also coincides with the full moon this month. The moon is set to appear full for a day or so on either side of the eclipse from Saturday to Tuesday.
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