October has been a busy month for sky enthusiasts, starting with a total lunar eclipse and followed up by an encounter with a Martian comet. Next, we will round out the week with a partial solar eclipse! Before we get to the details of where and when though, let’s have a crash course on solar eclipses.
There are three main types of solar eclipses: partial, total, and annular. As the name implies, a partial solar eclipse is when the Moon only blocks out a portion of the Sun’s surface. It will appear to the viewer that the sun has a “bite” taken out of it. This is the kind we’ll see this week.
A much rarer total solar eclipse occurs when the Moon completely covers the surface of the Sun, turning day into night and allowing only the solar corona and prominences to be seen. The last total solar eclipse visible from the U.S. was in 1991 over Hawaii. The one prior to 1991 was in 1979 and visible in the Northwest.
In between these two is the annular solar eclipse. This happens when the Moon completely moves over the Sun’s surface but doesn’t block out the sunshine entirely. This happens because even though the Sun and Moon appear almost the same size in the sky, there are slight fluctuations. This is due to the eccentric orbits of the Moon around the Earth and the Earth around the Sun. During an annular eclipse, the Moon appears slightly smaller than the Sun so it allows a ring of sunshine to still shine through, producing a “ring of fire” or donut-shaped sun. This was the last type of solar eclipse seen by most of the U.S. in May 2012.
Ok, enough of the astronomy lecture – now for the viewing details. The eclipse will happen Thursday evening, October 23 — unless you’re in extreme northeastern Maine, where you will be out of luck; the sunset will occur just as the eclipse gets underway. In general, the farther north and west you go, the more of the eclipse you’ll be able to see. Along the Eastern U.S., you’ll want to look toward the western sky a little before sunset Thursday, while residents in the West will get to see the entire eclipse while the Sun is still fairly high in the sky.
Written by: JOHN BATEMAN,WeatherBug Sr. Meterologist – continue reading at WEATHERBUG