How to Watch Tonight's Total Solar Eclipse

The moon and the sun are about to come together for an event people have been going gaga over since they realized it wasn’t a sign of the apocalypse. An occurrence that usually happens only once a year, the upcoming total solar eclipse will be visible to people in parts of Southeast Asia beginning around 8 a.m. on Wednesday. Because that part of the world is about a full day ahead from the United States, we can watch it all live on NASA TV at 8 p.m. on Tuesday. The peak of the show — when the sun is fully covered — will be from about 8:38 to 8:42 p.m. EST.

On Monday, NASA’s Marshall Space Flight Center, located in Huntsville, Alabama, took to Facebook to answer the solar-curious questions of the masses.

The comment-and-reply formula touched on questions like “Is it bad to look at the solar eclipse without glasses?” (yes) and “What is the temperature on the surface of the moon illuminated by the sun?” (the temperature doesn’t change from its cool 253 degrees.) Most wanted to know if they were going to be able to see the solar eclipse in person, which, if you don’t live in Southeast Asia, is no. But people in parts of Alaska, Hawaii, Guam, and the America Samoa will be able to see a partial eclipse.

NASA’s Facebook representative, which the organization only described when pressed as a “NASA Solar physicist who has studied the sun for over a decade,” also told commenter Adrian Kositanot that scientists on International Space Station aren’t likely to see the solar eclipse. But there is a chance the astronauts aboard will see a partial eclipse, as will some ESA satellites, if the orbital mechanics align just right. In 2006, the ISS crew was able to see the shadow of the moon as it fell on Earth.

While NASA replied Monday that this upcoming eclipse is “as important as any total solar eclipse!”, scientists are still stoked for the opportunity to study the lower solar corona from Earth. The corona is the faint solar atmosphere that can only be observed while the sun’s face is completely covered by the moon. Although the moon is 400 times smaller than the sun, it is also 400 times closer than the sun is to Earth — which allows the moon to block the sun’s face while only obscuring a small portion of the inner corona.

When scientists study the corona, they are able to scan the light for information about the temperatures and velocity of the electrons within it. This region is thought to be one of the most scientifically interesting areas of the sun — the goal is that by studying, scientists can learn about the acceleration of solar wind, how the corona is heated, and how clouds of solar material are made.

To study this solar eclipse, NASA scientists are setting up on the Micronesian island of Woleai, which is about 500 miles north from New Guinea in the Pacific Ocean. When the eclipse’s totality reaches them, the team plans on taking 59 several-second exposure shots in about three minutes with a newly designed camera. This new camera uses thousands of tiny polarized filters to read polarized light and, compared to the previous camera used, is able to cut down the length of time to take a exposure shot by 50 percent.

The totality, the moment when people below can see the full eclipse, will last about one to four minutes for each region. Estimated to be about 97 miles wide at its widest point, the path of the totality for this solar eclipse is expected to be 8,000 miles long. It should be three hours between when the westernmost location gets to see the eclipse and when the easternmost location sees it all end. As the solar eclipse will happen in the daylight for those in Southeast Asia, it’s going to look like the day has a twilight cast to it — the sky more lavender than blue.

Solar eclipses are only possible because of very precise geometry — because the moon and sun don’t orbit in the exact same plane, it’s rare that they line up just right. While there are two to five solar eclipses a year, a total eclipse only happens about every one to two years. The next time North Americans can enjoy a total solar eclipse will be in 2017.

If anyone has further pressing questions, NASA solar scientists will be participating in a Reddit AMA on Tuesday at 1 p.m. eastern time.