I am 83% excited about the “Ring of Fire” partial annular eclipse that will be visible from Sacramento on October 14.
Please don’t get me wrong; any astronomical occurrence that gets people looking up and asking questions about how the universe works brings me real, core-of-my-soul joy. It’s just that partial annular eclipses don’t have the “wow” factor of total eclipses. And I like to set expectations properly: Will this eclipse be the greatest thing you ever saw? Oh my, I hope not! Will it be totally awesome, anyway? Yep. And I can almost guarantee that you’ll be talking about it for years to come.
Let’s get you up to speed on the upcoming eclipse and calibrate your expectations, so you can fully appreciate what you’ll be seeing.
What will you see from Sacramento? Starting at 8:05 a.m. on Saturday, October 14th the disc of the Moon will begin to creep across the disc of the Sun. An hour later, the Moon will cover 83% of the Sun. (See why I’m only 83% excited, now?) Then, for the next hour and a half or so, the Sun will “re-emerge” as the Moon slides past it.
Now, keep in mind that the 17% of the Sun that will be peeking out at the peak of the eclipse is still plenty bright. You absolutely need approved eclipse viewing glasses to view the sun – do not try to look at the eclipse without them!
That covers what you’ll see. How about a little bit about why we’ll be seeing this?
A solar eclipse occurs when the Sun, Moon, and Earth line up so that the Moon blocks our view of the Sun. By a happy coincidence, the Sun and the Moon appear to be about the same size in the sky, so that when the Moon crosses in front of the Sun just right, some people on Earth get to see the Moon completely block out the disc of the Sun. The happy coincidence is that the Sun’s diameter is about 400 times that of the Moon, but the Sun also happens to be about 400 times farther away from Earth than the Moon. What luck!
Image credit: Jeff Rodgers
“On average” is the key phrase, here. Both the Earth’s and the Moon’s orbits are elliptical; that is, they’re not perfect circles. In its orbit around Earth, sometimes the Moon is a little closer to us and sometimes a little farther. On average, the Moon is 238,900 miles away from Earth. But on October 14, it will be 248,192 miles away, or about 3.89% farther away than average. At the same time, the Sun will be 92,697,390 miles away from Earth, or about 0.28% closer than average, making it look just a smidge larger. Taken together, this will make the Moon look about 3.6% smaller than average. That might not sound like much, but it’s just enough to allow the Sun to peek around the Moon’s edges, creating the annular eclipse’s “ring of fire” effect.
Image credits (left to right): Hinode/XRT, NASA/Aubrey Gemignani, NASA/Noah Moran
Now, keep in mind that we’re only going to see a partial eclipse here in Sacramento. Again, don’t get me wrong; getting to see any eclipse is special, and most of the world won’t see this one at all. To see the full “Ring of Fire” effect you’ll have to be in the path of the Moon’s umbra – the darkest part of the shadow cast by the Moon – which is a strip only 125 miles wide. (In case you were wondering, umbra is Latin for shadow and it’s the root of the word umbrella.) Just outside of the path you’ll see varying degrees of partial eclipse.
Image credit: Jeff Rodgers
We’re lucky that Sacramento is really close to the path of the umbra. We’ll get to see the Moon cover 83% of the Sun, which is definitely not something you get to see every day. In fact, just writing about it pushed me past 83% on the enthusiasm scale. I’m a solid 100% now!
I hope that you are, too. If so, we’ll be hosting a free eclipse viewing party at Matsui Park (see map below) from 7:30 – 11:00 a.m. with a solar-viewing telescope and complimentary solar glasses for you. Or, if you can’t join us but need safety glasses, we have them available for purchase in our shop. If you plan to join us at Matsui Park, you’ll want to park at the museum (parking fees are in effect) and walk over to the park, which is next door to the museum, just to the south. The museum’s restrooms will be open all morning, and we’ll open the museum to visitors at 9:00 a.m., should you want to follow your eclipse viewing with a visit to the museum.
Clear skies and hope to see you at Matsui Park on the 14th!