Will Any Human See Tomorrow’s Annular Solar Eclipse?

Simulation of tomorrow morning’s ring eclipse from Antarctica. The eclipse belongs to a rare variety of solar eclipses called ‘non-central’, where the moon’s shadow nearly but not quite touches Earth’s surface. Credit: Tom Ruen with additions by the author

If you’re looking for an astronomical event so remote that no one would ever bother to see it, tomorrow’s solar eclipse fits the bill. The moon will cover all but a thin ring of sunlight for any beast or bacterium that happens to look up from a tiny spot on the Antarctic ice at latitude at 131 degrees east and 79 degrees south. Not only is the event remote, it’s also brief, lasting all of 49 seconds.

Animation showing the eclipse path through Antarctica. The annular phase will only be visible from a tiny part of the continent for 49 seconds. You have to watch closely for the spot to appear along Antarctica’s upper right side. Times shown are Universal or Greenwich Time (subtract 5 hours for CDT). Credit: NASA

The eclipse is annular, meaning that the moon is too far from Earth for it to completely cover the sun, leaving a “ring of fire” or annulus of sunlight during what would otherwise be totality.

Annular eclipses aren’t rare, but this variety of annular eclipse turns out to be one of the rarest because the central axis of the moon’s shadow misses Earth’s surface by only a few miles. What does this mean?

It’s a bit obscure but boils down to this. No one anywhere along the eclipse path will see the moon exactly centered on the sun’s disk during maximum eclipse. OK, not a big deal, but oh so rare.

Now if you wanted to see the moon completely cover the sun, at least momentarily, you’d have to launch yourself into medium Earth orbit at an altitude of around 3,100 miles (5,000 km). Only then would you be close enough to the moon for it to fit over the sun, affording a brief glimpse of totality.

Astronomers call this particular flavor of eclipse “non-central with one limit”. The center of the moon’s shadow – called the antumbra in an annular eclipse – touches down in Antarctica at 12:57 a.m. CDT followed by the maximum ring eclipse just 6 minutes later. Six minutes after that, the shadow lifts off Earth and the annular eclipse is over.

Eclipse event experts Jean Meeus and Fred Espenak point out that of 3,956 annular eclipses occurring from 2000 BC to 3000 AD, only 68 (1.7%) are of the non-central variety.

Diagram showing the spot where the sun will briefly appear as a fiery ring during maximum solar eclipse. The southern Indian Ocean and Australia will see a partial eclipse. The numbers from top to bottom indicate what percentage of the sun will be covered: .80 = 80%; .40 = 40%. Credit: Fred Espenak/NASA’s GSFC

Eclipse chasers would probably find a way to get there if the moon’s shadow touched the ground even for a few seconds, but ring eclipses don’t cut it when it means spending tens of thousands of dollars to freeze your butt off on the most remote spot on the planet.

Skywatchers in Australia will still have a fine show of it, where about half the sun will be covered in partial eclipse. Even you and I will be able to watch the partial phases live on our home computers courtesy of SLOOH which will webcast the stellar show from Australia.

There’s a catch though. Broadcasting starts at 1:30 a.m. Central Time Tuesday morning, a time so remote that few will venture there.

10 Responses

  1. Richard Keen

    “If it were possible to launch yourself into low Earth orbit, you’d be close enough to be swept over by the moon’s shadow and catch a brief glimpse of totality”
    I don’t think that’s quite the situation here – methinks the “non-central” bit means the center line of the eclipse misses the earth, so on the ground the eclipse is a ring that is not centered on the sun. You can catch an Antarctic rocket flight to the proper height to be on the center line, and see the moon exactly centered on the sun’s disk – but it’s still annular.
    Fred Espenak’s eclipse diagram http://eclipse.gsfc.nasa.gov/SEplot/SEplot2001/SE2014Apr29A.GIF
    gives an eclipse magnitude of 0.9868, which means the moon appears 1.0000 minus 0.9868 or 1.32% smaller than the sun. So, once you get on the center line a few kilometers up you still must move 1.32% closer to the moon, or about 5000 km, to see a total eclipse. Perhaps some polar orbiting weather satellite will be in the right place.

    1. astrobob

      Thank you for pointing this out. I had read in other accounts that the umbral shadow was mere kilometers overhead, which did not make sense to me given the parameters. That’s why I assumed that low Earth orbit, which reaches up to 2,000 km, would be adequate. As you point out, a minimum of 5000 km would be needed. Thanks for the correction and I’ll update the blog.

  2. Troy

    Antarctica has many manned research stations, since annularity is so close to the coast I suspect somebody could see it.
    I’ve seen multiple sources say that it is impossible to have a total solar eclipse at the poles, but if you look at the March 20, 2015 solar eclipse that seems to be exactly what will happen.

    1. Kelly

      It is certainly possible for totality to occur at the poles, or any other spot on the planet for that matter. Although the Antarctic is the least favored location on the planet for total eclipses over the long run, the Arctic is actually the most favored (thanks to aphelion occurring during the northern summer, resulting in more chances for an eclipse to strike the further north you are when the sun appears a bit smaller – resulting in a total as opposed to an annular eclipse).

  3. Troy

    -93° wow that kind of puts the saying “no such thing as bad weather, just bad gear” to the test. Just imagine making the trek only to forget to remove the lens cap off the telescope.
    The partial eclipse in Australia will still be spectacular and the photographers down there never disappoint.

  4. Troy

    No, I’m in metro Detroit. It was tempting to stay up to see it (and the best part of any SLOOH program is the great commentary) but my day starts early.

    1. astrobob

      Yes, that would have been 2:30 a.m. for you. I was thinking now of BC Stargazer who often drops by.

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