The eclipse that will blaze across America a month and a day from now will follow a trail blazed in 2006.
Paths of the 2024 eclipse and its three predecessors and three successors in saros series 139. Ellipses along the paths are the footprints of the Moon’s total shadow, at 10-minute intervals.
The saros is a period of 18 years and about 11 days and a third of a day. It is caused by the lengths of three kinds of “month,” one of which is called the draconic month because it governs the Moon’s north-south undulations across the ecliptic and therefore whether the eclipse “dragon” can eat the Sun.
After an eclipse of the Sun or Moon, there comes, one saros period later, a similar eclipse. The discovery of this dates as far back as the Babylonians, and it results in a fascinating network of patterns in time, comprehensively explained and illustrated in pages 60-105 of our book The Under-Standing of Eclipses.
The successor eclipse is similar in most ways – such as how high it appears in the sky, how closely the Moon fits in front of the Sun, and the curve of the path across Earth. But one huge difference is made by that little one-third-of-a-day fraction. The whole eclipse happens about one third of the way around our planet. So the most similarity is between eclipses three saros periods – about 54 years – apart.
If you were on the east coast of North America in March 1970, you’ve seen what you will see a few hundred miles inland this April!
Each eclipse belongs to a saros series. Each series begins with a marginal eclipse in the Arctic or Antarctic, move gradually across the Earth, evolving in character, and dies out at the other icy extreme. As Astronomica Calendar 2024 says (page 98), “This is eclipse no. 30 of the 71 in solar saros series 139 (1501 to 2763 A.D.).”
Saros series 139 has a habit of cruising the eastern USA and Canada in a northeasterly direction, parallel to the Appalachian mountain system and sometimes along it like a tourist enjoying the Blue Ridge Parkway. The course this time lies more to the west, in the Mississippi lowlands, but the slant is the same. It is caused by the attitude of the spinning Earth in northern springtime, traveling with its north pole leaning backward.
A month and a day from now! If you are in, or plan to get to, Texas or Maine or a spot in between, be sure to understand the draconic spectacle you’ll see, and how to gaze with well-protected eyes as the Dragon swallows the Sun and spits out fire!
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My experience was similar to Andrew’s ~ I was 7 years old in 1970, observing the eclipse with my father in Richmond, VA. He was new to astronomy and had read that the eclipse would be 98% in Richmond, which he assumed would be interesting enough to not have to travel. I recall that the sky became a steel gray color. Had we just driven two hours down to Norfolk or Virginia Beach, we could have experienced totality. I too am planning to go to Texas to observe this eclipse 54 years after my first.
So, there I was as a 10 year old kid that Saturday 3/7/1970 at my Dad’s jewelry store in Jackson Heights, Queens (A borough in NYC) standing outside his store waiting for the eclipse to happen. And I saw nothing. It was a beautiful sunny day and this budding astro geek didn’t understand thing 1 about eclipses. I knew it was going to be partial at my location and I now know it was a 95% obscuration at my location. Many years later after minoring in astronomy at SUNY Oswego under the tutelage of Dr. Ron Chaldu, and seeing his slides of the eclipse in India 2/16/80, I knew I had to see at least one in my lifetime. Well, i got that chance for the 7/11/91 eclipse in Mexico and since then I have seen 3 more for a total of 4 totals. While knowing of this eclipse coming years and years ago I never realized it belongs to the saros series 139, the same one as that March 1970 eclipse. And here we are…54 years 1 month and 1 day later in a few weeks and I will be in Texas for my 5th totality. So, this one has special meaning to me as this is the saros that started me off learning more about astronomy and space science.
Saros 139 lore: In 1970 Carly Simon’s nameless vain lover flew his Lear jet up to Nova Scotia to see the total eclipse of the Sun.
Fortunate that the umbra is going right over my hometown, though Cleveland has 50% cloud cover in Early April. Of course that’s average. Days range from 0%-100%.
Hope you get to see it. It’s the Guardian’s home opener that day too. In case you like baseball