Having just returned from leading our Texas tour, we’re hearing lots of questions about how this total solar eclipse compares with others. It’s a fair question, especially to me, since I’ve been taking people to totalities for 54 years, and watched thousands deal with various eclipse issues all around the world. It was also a very special one, an aspect I share with the great Fred Espenak, who for decades has created all those detailed path-charts of totality for NASA Goddard and more recently on his own.
What we share is the odd word Exeligmos. Most people have heard of the Saros, a Babylonian discovery picked up by the ancient Greeks, who all realized that the same kind of eclipse repeats after 18 years, 11 and 1/3 days. It’s that “1/3” of a day which throws things off, because it makes the next eclipse happen one-third of an Earth rotation from the previous one. Meaning, it lands 120-degrees of longitude to the west of the last eclipse with similar properties.
Then a second Saros passes after 18 years, 11 1/3 days, another matching eclipse a further 1/3 of the Earth to the west. But here’s the kicker: After three Saroses, those 1/3 days add up to a full day, and the matching eclipse returns to roughly the same region as the first. Finally, a repeat.
Three Saroses, or three times 18 years and 11 /3 days, is 54 years and one month, and that’s an exeligmos. Well, Fred Espenak and I both saw our first eclipse in the southeast US on March 7, 1970, so the one that just happened marks one exeligmos for us both. We congratulated each other.
Anyway, how was this eclipse different? First it was the last to be seen in the Northeast US until 2079, a long time. It had mostly cloudy weather down in Texas, but we fortunately saw totality anyway. In the Northeast, weather conditions were generally good, and millions observed it and finally came to understand why a total solar eclipse is a million times more spectacular than a partial.
This eclipse also had unusually brilliant naked-eye prominences, those pink geysers of nuclear flame shooting up from the Sun’s limb. The biggest and brightest was on the bottom edge.
After this, for the next couple of decades, newly hatched eclipse addicts will have to travel overseas for a solar totality. To join me and our group, and see what we’re planning, check out specialinteresttours.com. You might just discover that you’re in it for the long haul.
Join the family! 
