Sunday, September 30, 2012

Ring of Fire

Among those celestial events observable by humans, solar eclipses have an unmistakable allure, so much so they’ve spawned an exclusive community of people called “eclipse chasers.” These adventurers research, plan, schedule, scheme, and ultimately travel anywhere in the world to be in the right place at the right time for eclipse events, especially rare total solar eclipses.

A solar eclipse occurs when the Moon passes in front of the Sun, as seen from Earth. Oftentimes the alignment is imperfect, resulting in a partial solar eclipse. However, if the Moon completely covers the Sun from our perspective, a total solar eclipse ensues. And if the alignment is good, but the Moon is at a point in its orbit where it’s too far from Earth to completely cover the Sun, an exposed ring of sunlight surrounds the dark lunar disk. This third type of solar eclipse is called an annular eclipse, from “annulus,” Latin for “ring.”

On May 20, 2012, an annular eclipse was visible from Asia to western North America, stretching across the Pacific. Fortuitously, the path of annularity, a 200-mile-wide swathe where the “ring of fire” was visible, crossed New Mexico and was centered on Albuquerque. Although at this locale the eclipse began around 6:30 p.m. and was still in progress at sunset, most of it was observable. The impending event created lots of buzz in the local amateur astronomy community, not to mention among the general public and photographers at all skill levels. Albuquerque became a destination for astronomy enthusiasts from across the country.


World map of the May 2012 solar eclipse
Line of red circles = path of annularity
Figure by Fred Espenak, NASA

My email inbox lit up with discussions of eclipse-related timings, techniques, equipment, locations, phenomena, and media misinformation. We fretted over how cloudy the western sky had been lately. We verified the next annular eclipse visible in our area would occur in 2023. We identified an upcoming (2017) total solar eclipse visible from the U.S. (rare!) and evaluated both Kentucky and Wyoming as prospective viewing destinations (Wyoming won).

My experience of the May 2012 annular eclipse, which I’ve recounted below, was a highlight of my observing life thus far. And best of all, it came right to my doorstep. If you’ve not seen one, I recommend you put it on your bucket list immediately!


Eschewing the designated public viewing site in Albuquerque where a crowd of 10,000 would gather, we were seven strong at my astronomy club’s remote observing site. I was joined by club members Jeff, Bill, and Carl, as well as two visiting amateur astronomers from the Kansas City Club and one from Florida.

The Kansas City folks were particularly thankful to be there. Arriving in Albuquerque, they had tried contacting our astronomy club through its website without success, somehow found (unpublished) coordinates for the observing site, entered them into their GPS, and started driving.

They got lost. They had no idea where they’d ended up: “in the middle of nowhere,” as they put it. After a while, a young man came along in his car. They told him they were trying to get to the astronomy club’s site. He led them through the wilderness, deposited them at the gate, and vanished in a cloud of dust. Ah, the kindness of mysterious strangers.

Like an eating-contest contender training for gluttonous excess, I had methodically prepared to cram as many experiences as I could into the hour-and-a-half-long event. It was, after all, my first solar eclipse observation, and I wanted to make it count. So I had with me four pieces of welder’s glass of varying densities, 10x50 binoculars equipped with black polymer solar filters, an 80mm refractor telescope equipped with glass solar filter and 25mm eyepiece, and a piece of plywood drilled with several 7/64-inch holes—for making pinhole projections during annularity, the fleeting Ring of Fire phase.


Welder’s glass and curious beetle


My observing colleagues also came prepared for observing or imaging the event safely, with properly filtered equipment. We scattered along the full length of the observing field, extravagant in our use of the flat, graveled expanse and its big-sky vista to the west.

Carl set up to image with a Canon DSLR, shooting through our club’s vintage 6-inch Astrophysics refractor. Brent from Florida was also imaging, with one DSLR shooting through his refractor and a second piggybacked on his mount. The Kansas City duo was observing with a 10-inch Dobsonian reflector telescope. Jeff was packing eclipse glasses and a refractor. Bill busied himself with fine-tuning the club’s new astrophotography equipment.

In my haste to get to the site, I’d forgotten one critical piece of equipment:  a hat. The bright, hot, cloudless afternoon boded well for eclipse visibility, but my deficit in headwear quickly became uncomfortable. Fortunately I was able to borrow a ball cap.

DeAnna and Leonard, a couple from the nearest town, arrived unexpectedly and parked their big truck precisely between our equipment and the Sun. Oops. At our urging, they hurriedly and abashedly moved their vehicle to a better spot. Although outfitted with their own eclipse glasses, they were nevertheless curious to see what was happening at our observing site.

And then there were nine.


Eclipse watchers
Image by DeAnna


I’d brought an atomic clock from home so I could call out countdown times to each event milestone—called “contacts.” Thirty seconds to 1st contact—the beginning of the eclipse—I single-mindedly plastered my eye to my refractor, because it would present the most magnified view.

Before I actually saw the Moon’s silhouetted disk slide into view, I noticed that something was happening on the Sun’s outer edge, a sort of subtle bubbling effect. Then the Moon took its first visible nibble, accompanied by a sudden frenzy of drumming from the crowd of New Agers who’d gathered at their ceremonial site half a mile away.

It had begun.


First nibble by the Moon - lower right, at 4 o'clock position

Throughout the eclipse, I was moving continually among my color and magnification options—thrilled alike by the unmagnified lime green view through #12 welder’s glass, the magnified-10-times deep orange view through the binoculars, and the magnified-16-times yellow gold view through the refractor. Of course, we all shared views with one another through our array of equipment, even taking turns looking through Jeff’s vintage eclipse glasses, a souvenir from the 2001 total solar eclipse he’d traveled to Africa to see. Together we witnessed the usually benign Moon relentlessly devour each of three large sunspot groups on our freckle-faced star.


  Hungry Moon advances on a sunspot


At one point, Bill said, “Hey, turn around and look at our shadows.” We twirled in unison. Replacing our familiar shadows was a menacing band of gangly creatures with hideously misshapen heads and curiously deformed fingers, rendered otherworldly by the lunar cutout.

About an hour into the eclipse, the Moon was almost entirely inside the Sun’s disk. At 2nd contact, it pulled away from the Sun’s limb (outer edge), and we had our first exhilarating look at the Ring of Fire. I moved, mesmerized, from view to view to view of that impossible ring suspended in the evening sky:  blazing, bodacious, biblical.


Ring of Fire, as seen in refractor eyepiece
Image by DeAnna


Overhead, powder blue deepened to cornflower. DeAnna held her smart phone to the refractor eyepiece, snapped an image of the ring, and crowed, “Got it!” A nearby mockingbird took a deep breath and launched into a coloratura passage of trills, whistles, and high notes. At 30 seconds to mid-eclipse, I sprinted—with perforated plywood and camera—to the sunlit side of a white travel-trailer for my first-ever experiment with pinhole projection.


With the Sun behind me, I shoot my shadow and my board's shadow on a white background.
Rings of sunlight stream through the small holes, showing the Sun in mid-eclipse.
So easy, and so fun!


A mere four minutes and nine seconds after 2nd contact, the unstoppable Moon kissed the opposite limb of the Sun for 3rd contact, the end of annularity. Planted at my refractor during both 2nd and 3rd contacts, I observed dainty Baily’s beads, one of the items on my eclipse wish list. More commonly seen during total solar eclipses, these are discrete beads of sunlight briefly shining through the valleys and other irregularities along the Moon’s outer edge, just before it pulls away from or connects with the Sun’s limb. Truly exciting to witness!

The end of annularity: 3rd contact


After the high drama of annularity, there was time for more leisurely pursuits. We looked for and spotted Venus high above the eclipse, waiting in the wings for her star turn: a very rare and much ballyhooed transit across the Sun in early June.

The Moon continued to move eastward in its orbit, slowly unmasking the Sun. Clouds drifted across the crescent Sun, flirting with the re-emerging sunspot groups. Sunset approached, and the partially-eclipsed Sun descended into atmospheric haze near the horizon. Needing less protective darkening as a result, I switched to the #11 welder’s glass, and it was just right.


Moon leaving Sun’s disk, as clouds drift by


The serrated western horizon began to gnaw on the abbreviated Sun. We knew we wouldn’t see the end of the eclipse, 4th contact, when the Moon’s disk completely leaves the Sun, because sunset would occur first.

As I drank in another long, satisfying look through the telescope, a fissure suddenly opened on the Sun’s surface. What the ???!  Realization dawned. “Jet trail on the Sun! Shoot! Shoot!” I yelled, and the imagers began clicking furiously. Big orange jack-o’-lantern grin. Shark fin. Glowing ember. Gone baby gone, ushered out with another flurry of drumbeats.


Partially eclipsed Sun with jet trail
Shark fin:  the still-eclipsed Sun sets


Do it again. Oh, do it again. Please? Finally I understand the compulsion, the addiction, the fever that grips eclipse chasers. Must. Find. The. Antidote. I hear it’s in Wyoming.