05 December 2012

Three Minutes in the Moon's Shadow

My awesome MS-Paint rendition of a total solar eclipse progression. You know you love it.

Last month I had the unforgettable experience of watching a total solar eclipse for the first time in my life. I'd say it is, hands down, the most spectacular natural phenomenon that you can observe with the naked eye.

It's a sight that many people only get to see in pictures and videos during their lifetimes, unless they happen to live in the right place at the right time or have the wherewithal to travel there.

Given that I married into a family whose favorite pastime is travelling the world to observe solar eclipses, I'd say I lucked out. They've been everywhere from the jungles of Zambia to a plane flying over the Arctic ice to watch the moon blot out the sun for just a few minutes at a time. They're self-proclaimed eclipse chasers, and my father-in-law runs a website and blog dedicated to their hobby.

My in-laws decided that it was time for me to lose my eclipse virginity, so they brought me along on a voyage to the South Pacific.

(For an excellent interactive map of where this eclipse was visible, you can go here.)

Some eclipse chasers elected to go to Australia to view this eclipse from land. Our group had a different idea.

Our destination:

And so we traveled to Fiji, and left on a cruise ship chartered by a bunch of astronomy nerds for the specific purpose of seeing the eclipse at sea. Having not yet seen an eclipse, I was amazed at the lengths that people would go to in order to get good seats to the show. I was certainly looking forward to the trip, but still had no idea how amazing the experience would be.

For the uninitiated, here's a quick explanation of some eclipse jargon:

  • Total solar eclipse: when the moon (during an approach closer to Earth) moves directly in front of the sun and blocks it out completely; the brief period of time in which this happens is called totality
  • Annular solar eclipse: when the moon (during an approach farther from Earth) moves directly in front of the sun and blocks out all but a ring of the sun's surface around its outer edge (not as awesome as a total eclipse)
  • Partial solar eclipse: when the moon crosses the sun's path in the sky but does not fully eclipse it (also not as awesome as a total eclipse)
  • First contact: the moment when a tiny bit of the moon's silhouette first appears in front of the sun, beginning the eclipse
  • Second contact: the moment when the last sliver of the sun disappears and totality begins, marked by a "diamond ring" effect
  • Third contact: the moment when totality ends and the sun starts to reappear, marked by a second "diamond ring" effect
  • Fourth contact: the moment the last bit of the moon's silhouette disappears from in front of the sun, thus ending the eclipse.
  • Solar filter: a sheet of material that blocks at least 99.997% of incoming light, through which it's safe to look at the sun.
  • Corona: a layer of extremely hot plasma surrounding the sun; it's the distinctive halo/aura around the moon during a total solar eclipse.

Before the eclipse

What struck me the most in the days leading up to the eclipse was the excitement in the faces and voices of the veteran eclipse chasers anticipating the event. I've scarcely seen this kind of enthusiasm. A rather religious passenger on the ship compared the sight of totality to "the eye of God"; a less religious passenger compared it to "a Grateful Dead concert, without the drugs." I didn't personally identify with either example.

Obviously seeing an eclipse was a very emotional experience for some people. I wasn't sure I'd react the same way. I mean, yeah, I thought eclipses looked really neat in all of the photos and videos I'd seen, but can seeing one really have such a profound effect on adults (most of whom have a thorough understanding of the science involved) who have seen them before?

An often-repeated sentiment was that although totality is typically a few minutes long, it feels more like eight seconds.

One of the astronomers on board would be on the bridge with the captain on eclipse day, making certain that we navigate to get the best possible view of the eclipse in the region. Avoiding cloud cover while staying in the path of the moon's shadow was the priority, second only to keeping the ship afloat.

The evening before the eclipse, my father-in-law gave a presentation in the ship's auditorium about photographing the eclipse. The major points of his talk:

  • Don't stare at the sun without a solar filter (except during totality) or you will permanently damage your eyes;
  • Never point an unfiltered scope of any kind at the sun (except during totality) or you will fry your retinas and/or boil your eyeballs out and/or probably set something on fire;
  • Turn off your flash! If your camera flashes during totality, you will be summarily thrown overboard by an angry mob (this protip/half-serious threat was repeated several times);
  • If it's your first time, don't waste precious seconds of totality fiddling with a camera. Just enjoy the show.

Well, it was my first time, so I planned to sit back and enjoy the show. I'd leave the eclipse photography to the people who knew what they were doing.

Eclipse day!

I woke up and got to the top deck just in time for the astronomer on the bridge to announce that first contact had occurred. The more hardcore eclipse chasers had been on deck since the wee hours of the morning setting up their telescopes and cameras; I just walked on as the show was starting.

My wife and I looking at the partially eclipsed sun through our filters, rocking our Eclipse Chasers t-shirts. My sister-in-law, Melissa Kramer, designed the logos.

Sure enough, when I put my solar filter glasses on I could see the tiny little nibble the moon had taken out of the solar disk. Interesting to see, but nothing spectacular.

Here's what you see through a solar filter. © Denise Kramer, 14 Nov 2012.

The next hour was a slow crawl from first to second contact, so I took the opportunity to look around at what the other passengers had set up on deck.  There were telescopes and cameras on tripods, and one couple's setup (which I did not get a chance to photograph) with several of both rigged with makeshift counterweights made from bottles of water to account for the ship's slight rocking.

It's probably unusual to see this many telescopes on a cruise ship in the South Pacific.

I checked on the eclipse's progress periodically, as it happens too slowly to notice a difference if you keep staring at it. I spent the time watching the other changes that happened as the solar disk vanished. The temperature dropped. Shadows became sharper due to the smaller light source. The sunlight reflected on the water looked like it does at sunset. The darkening sky took on the color scheme of twilight, with an orange hue appearing at the horizon on all sides. Wherever sunlight passed through a tiny opening, the ever-diminishing solar crescent was projected on the surface behind it.

Neat trick: you can create a pinhole camera effect with your hands to project the sun's image onto your shadow. That projection will show the crescent sun during an eclipse; look at the full-size image to see the crescents between Bill's fingers.

The eclipse's progression almost seemed to speed up as totality drew nearer.  The sun, still too bright to look at directly, looked like a tiny filament through the filter.  I watched intently as it grew thinner and thinner until I finally I heard someone shout, "diamond ring!"

I knew then that it was time to put the filter down, and what I saw was just as breathtaking as it was hyped up to be. Pictures really don't do it justice; even the sharpest, most detailed photographs don't compare to seeing totality with the naked eye.

The diamond ring! © Denise Kramer, 14 Nov 2012.

At second and third contacts, "beads" of direct sunlight shine through the valleys along the edge of the moon. Looking at them directly is risky, but I'm told that a few seconds' exposure shouldn't do any permanent damage. I decided to take that risk and briefly observed the "diamond ring" effect through unfiltered binoculars. It was worth it.

After the last bead disappeared, I could just make out the sun's pinkish-red chromosphere, a feature that is only visible during a total eclipse.

Totality. © Denise Kramer, 14 Nov 2012.

During totality, I took a few seconds to look around a bit. Venus was clearly visible overhead; it was the brightest thing in the sky, save the corona. People who knew exactly where to look said that they saw Mercury and Saturn, but I didn't want to get too distracted looking for planets.

A wide-angle shot during totality. © Bill Kramer, 14 Nov 2012.

I spent most of totality gazing at the corona with my own eyes, but used my binoculars to get a closer look. Time seemed to stop during totality, and yet somehow the three minutes felt like they were over in less than one. The astronomer on the bridge must have been lost in the moment as well, as he missed making his halfway point announcement and abruptly rang in with "Twenty seconds! Twenty seconds remaining!" on the PA at what felt like five seconds before third contact.

Here's a video capturing the passengers' reaction to the second diamond ring (and thus the end of totality), courtesy of Melissa Kramer:

And just like that, totality was over. The second diamond ring was just as beautiful as the first, and then the sun was once again too bright to view directly. The filters went back on, and we watched the events of the last hour happen again in reverse.

A tiny sliver of sun reappears after third contact. It may not look like much, but it's enough to permanently blind you through an unfiltered telescope. © Denise Kramer, 14 Nov 2012.

The aftermath (afterglow?)

The ship's staff, who had taken a break from their duties to watch totality with us, handed out glasses of champagne and bottles of Corona to celebrate a successful eclipse voyage.

The span of time from third to fourth contact doesn't have the same excitement as does the span from first to second. There anticipation before totality and the diamond rings has passed, and all that there is left to do is bask in the afterglow.

One passenger had plans on making this phase more interesting, though.  Several minutes after third contact, a pre-recorded message played over the PA, stating that at this eclipse we'd be seeing a third diamond ring. This passenger then dropped to his knee and proposed to his girlfriend, whom it turned out he had originally met during a solar eclipse. The ring itself was even crafted to look like a solar eclipse - the top was a black disc, encircled in white gold with a diamond at the edge. I thought it was rather clever and cute.

After the obligatory congratulations to the newly engaged couple, the crowd started to thin out. A few people stayed to study the sun and take photographs until the partial phases of the eclipse were over, but I was content just glancing at it periodically as the moon's silhouette retreated.

Epilogue: Go See an Eclipse!

Before I saw this eclipse, I was skeptical about the hype. Now I'm convinced that the experience lives up to it. It doesn't matter if you're an astronomy nerd or just an ordinary person who can appreciate the beauty of the cosmos. I absolutely recommend that anyone with the means to do so goes to see at least one total solar eclipse (don't just settle for an annular or partial) during their lifetime. When you do, you'll understand why I speak so highly of it.

Luckily for those of you living in the continental US, you'll get your chance soon. On August 21, 2017 we'll have a total solar eclipse cut across North America from Salem, Oregon to Charleston, South Carolina. It will be the first time a total eclipse has been visible from coast to coast in the US since 1918.

If you're in its path, make plans to watch it. If you're not in its path, make plans to be there on that date. You'll be glad you did.

(Cross-posted to Skeptic Freethought)

Creative Commons License

Creative Commons License