It’s August and one of the most highly-anticipated astronomical events of the 21st century is nearly upon us: the August 21 solar eclipse, which will be visible as a total eclipse literally across the entire United States…but that doesn’t mean everywhere in the United States. Totality will pass across the U.S. in a narrow band about 60 miles wide starting along the northern coast of Oregon at 10:18 a.m. local time (PDT) and ending along the coast of South Carolina at 2:48 p.m. EDT. But that’s just totality—the full eclipse event will actually begin much earlier than that and end later, and its visibility won’t be limited to only that path. And while it’ll be happening overhead in the daytime sky you’ll need the right equipment to view it safely, whether you’re in totality or not.
Wait, you say, what’s the difference between totality and…not totality? And how is it caused? And why is this a big deal at all? If you’re wondering those things (and perhaps others) then this post is just for you. Below are answers to some common—and certainly not dumb—questions about the solar eclipse, brought to you by yours truly (with a little help from NASA and other eclipse specialists.)
Totality — that brief period during a solar eclipse when the Moon is completely centered in front of the Sun’s disk — is a truly amazing sight, so much so that many people who have seen it once (a privileged group that doesn’t include me, sadly!) will travel across the globe in an effort witness it again and again.
During solar eclipse totality the sky not only becomes dark, dropping the temperature and sometimes even allowing stars to be seen, but also the Sun’s outer atmosphere is revealed around the silhouette of the Moon for a few short moments. Unfortunately this is not easily captured on camera because of the rapidly changing lighting situations, and when it is it pales in comparison to the real thing (or so I hear.)
The video above, taken during the November 14 eclipse from Queensland, shows the moments of totality pretty nicely although the streamer effect can’t really be made out. Still, we get a good idea of how the light changes and we can see another effect called “Baily’s Beads”, where sunlight peeks through some of the relief of the Moon’s terrain along its outer limb. Also the “diamond ring” effect can be seen as the Sun is uncovered.
Enjoy, and thanks to YouTube user solareclipse eclipsevidgvale for the upload!