Eclipse News

How to Predict the Next Eclipse / When is the Next Eclipse?


How rare is a total solar eclipse?  That is not an easy question to answer, especially when pinpointing the next total solar eclipse in a particular place.  When one looks at a map of a series of solar eclipses over any 100 year period, they appear to be a completely random event.  Some are partial or annular eclipses, about one in four is a total; some run north-south while others run west-east; some last only a few seconds, others push the maximum at 6 or 7 minutes; some have a wide path of totality near 200 miles, others (like this one) have much skinnier paths.

In Da Cosmic Mojo post we attempted to boil this all down to the phase, tilt and distance of the moon.  This is a simple explanation as to the why of eclipses but does nothing to illuminate the where and when.  For that, we need to see if maybe these events are not as random as they first appear.


Seasons in the Sun

Holiday, baseball, planting, skiing – many things have a season, including eclipses.  Eclipse seasons last for about thirty-four and one half days and repeat a few days shy of every six months.  Somewhere on earth, each and every eclipse season, a solar (and a lunar) eclipse will occur.  If the eclipse occurs early in the season, a second will occur in the same season; it is also possible for a part of a third season to squeeze in during a calendar year.  All of this means a minimum of two and up to five solar eclipses can occur within a calendar year.  The last time five solar eclipses occurred was 1935, a feat that will not be repeated until the year 2206.

Our old friend the lunar node is the reason for the eclipse season.  For these thirty four and one half days the sun is close enough to a lunar node – the point where its orbit crosses that of the moon from our earthly vantage – that a solar eclipse will occur.  Da Cosmic Mojo tells us the eclipse be one of three flavors:

The type of eclipse that we end up with is determined by how close the moon is to the node, and how far away the moon is at the time.


Saros Cycling

Every 18 years (plus a few days) an eclipse will “repeat” itself (similar path and duration) with one difference – it will occur about 1/3 of the way around the globe from its predecessor.   This pattern in eclipses is known as a Saros Cycle.  Related eclipses within a Saros Cycle span between twelve and fifteen centuries and produce 78 eclipses, on average.  The cycle begins at one of the poles with a series of partial eclipses, moves toward the equator as partial, annular and total eclipses before ending at the opposite pole.  To further confuse us there are currently about 40 active Saros Cycles and, for the record, the August 21st event is the 22nd of 77 eclipses making up Saros 145.

If you want the deep dive on eclipse predicting, maps and data take time to explore Fred Espenak’s work on the NASA Eclipse Site as well as, where you will also find his stunning eclipse photography.  To find out about upcoming eclipses at your location simply plug it into the eclipse calculators at and NASA.


Just the facts, Ma’am

Got it straight?  Yeah, me neither.  Let’s end this edition with some solar eclipse facts that just might help sort out the complex cycles of solar eclipses.

  • Although 2 and up to 5 solar eclipses can occur in a calendar year, total solar eclipses occur only once every 18 months (2 in 3 years)

  • For any given spot on earth, a total solar eclipse recurs once every 360 years or so…..on average

  • For any given spot on earth, a partial solar eclipse is visible about once every 2 years…..on average

  • In this century there will be 224 eclipses on planet Earth; 77 partial, 70 annular, 67 total and 7 hybrid eclipses

  • In this century there will be 11 annular and 11 total eclipses that touch some part of the US (Alaska and Hawaii included)

  • Two spots in the US will see 2 total solar eclipses in 7 years – Carbondale, IL (2017 / 2024) and Altha, Florida (2045 / 2052); one spot, Nimrod Lake in Arkansas, will see 2 in 21 years (2024 / 2045)

  • Los Angeles will not see another total solar eclipse for almost 1,500 years

  • The southeastern US is going to have a really good century for total solar eclipses  

 Copyright (C) 1995-2017 Ian Cameron Smith

I am constant as the northern star,
Of whose true-fixed and resting quality
There is no fellow in the firmament.

William Shakespeare, Julius Caeser, act 3, scene 1

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