In the Shadow of the Moon

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As in all these blog posts, any pictures below are all linked to full-sized versions.

From the northwest corner
of a brand-new crescent moon
crickets and cicadas sing
a rare and different tune
in the shadow of the moon  

Robert Hunter/Jerry Garcia - The Grateful Dead

Great American Eclipse, August 21, 2017
Total Eclipse, Aug. 21, 2017 - (Regulus in lower-left)

Solar eclipses are not rare. Somewhere on earth, between two and five eclipses occur every year. The trick is being in the shadow of the moon when one happens. 

An eclipse is an almost stationary event. The sun doesn't move. The moving piece, the moon, crosses between the earth and sun in its orbit around the earth, a relatively slow event witnessed from the human time scale. The path of a solar eclipse on the surface of the earth is created by the earth's rotation on its axis. The speed of the eclipse, on the other hand, is determined by the earth's rotational speed at the latitude you happen to be observing from. At the equator, the rotation speed is 1037 miles per hour. That speed decreases with distance from the equator by the cosine of your latitude. At 41º North Latitude, the equation would be, cos (41) = 0.755 x 1037 = 783 MPH.

During a solar eclipse, when the moon travels between the sun and the earth, two shadows are cast by the moon. Since the sun is so much larger than the moon, sunlight still passes around the moon creating a faint shadow surrounding a darker, inner shadow. This dark, inner shadow is the center of the total eclipse. The shadow created by light passing around the moon is known as the penumbra. Where the penumbra falls on earth, viewers witness a partial eclipse. The dark, central shadow created by the moon blocking the sun's light is called the umbra. Where the umbra is cast on earth is where totality occurs. 

Illustration showing penumbra and umbra
The Moon...A Shady Character

The solar shadows remain relatively stationary in space, but the earth is always rotating on its axis. As this rotation happens, a path is created under the aligned moon and sun. The path the umbra creates is called the path of totality. The center of the path of totality is where the duration of actual total eclipse is longest. Moving away from the center line, the duration becomes shorter. Traveling away from the center of the umbra, you will eventually cross over the edge of the path of totality and into the penumbral shadow. During an eclipse, when viewed from beneath the penumbral shadow, the moon will appear to cover less than 100% of the sun's disc. The umbral shadow, the path of totality, is usually about 100 miles wide, 50 miles either side of the center line.

I've been an eclipse fan since I was a young lad. I got a telescope for a birthday, not sure which birthday it was, but that scope and I became inseparable. There is a picture of me holding the projection of a partial eclipse in my hands one early morning. The picture is dated December 1974, so it was the December 13th partial eclipse. That one rolled over me at 856.5 MPH and never stopped.

Author showing eclipse in 1974
December 13, 1974

Since then if there was an eclipse happening with me under it, I was gazing at it somehow, whether projecting it through binoculars, or simply looking at the images of the projected sun filtering down to the ground from between the leaves of a tree. I had always dreamed of viewing a total eclipse, but my life span so far has coincided with a 99-year dry spell for total eclipses in North America. Between June 8, 1918, and August 21, 2017, a few total annular eclipses, events that leave a ring of the sun still visible around the moon at totality, made their way across the continent, but as for complete eclipses, convenient areas of the North American Continent were completely shunned by the dragon of totality.

Projecting eclipse onto rock
October 23, 2014 - Tucson, AZ

May 20, 2012

The moon moved between the sun and earth over eastern China, and as the earth rotated, the umbra raced northeast over the Pacific Ocean, arcing just south of the Aleutian Islands, continued around the Gulf of Alaska and turned south, paralleling the western coast of Canada, but remained over the Pacific. Totality crossed onto the North American Continent near Crescent City, California. It continued southeast, passing through central Nevada, southwestern Utah, northeastern Arizona, diagonally across New Mexico, then ended in the southern Panhandle region of Texas.

As the center of the umbra barreled across the border between Utah and Arizona at 833.6 miles per hour, I was directly in its path.

This was a total eclipse, but a different type of totality was reached. The moon's orbit around earth is not a perfect circle, it's an ellipse, or egg-shaped path. During this eclipse, the moon was at one of its furthest distances from earth, making it appear smaller than the disk of the sun. During eclipse totality, a ring of the sun remained visible surrounding the moon, prompting the common name for this eclipse type, the Ring of Fire. While still within the umbral shadow of the moon, on the center line of totality daylight remained, diminished but not extinguished.

Annular or 'ring of fire' eclipse
Annular "Ring of Fire" Eclipse, May 20, 2012

I journeyed from Tucson, Arizona north to the small community of Page, north of Flagstaff on the Utah-Arizona border. I overnighted in Flagstaff and made my way north in the morning, passing through the red rock desert of the Colorado Plateau, my personal favorite place on earth. I arrived at the spot I had chosen, Horseshoe Bend. Situated atop 1000-foot sandstone cliffs overlooking an entrenched bend of the Colorado River, I thought it would be an impressive place to view and photograph my first total eclipse.

Arriving six (6) hours early for the event, imagine if you will my shock and amazement at being turned back at a barricade by a policeman who explained that there were over 1000 people already at the small overlook, that has parking for about 150 vehicles. This was something I had overlooked in the small amount of research I performed: my fellow humans. 

I was able to find a turnout at the Waterhole Canyon trailhead down the road about 3 or 4 miles that would offer the same view of the eclipse with only a tenth of a second difference in the duration of totality, but with a thousand or so fewer of my fellow bipeds. I set up my equipment, a telescope and table laid on its side. I taped a piece of poster board to the table. When the eclipse began, I would project its image through the telescope onto the makeshift screen.

Ring of fire eclipse
May 20, 2012 - Page, Arizona

As the time for the eclipse drew near I aligned the telescope and began projecting the solar image. A car pulled into the turnout and the occupants got out and asked if they could join me, having been met by the same masses I had been at Horseshoe Bend. I was happy for the company. Over the course of the event, about 30 people joined us. It was a remarkable experience that I enjoyed. 

It was on the way home that evening in May 2012 that I began planning for the August 21, 2017 total eclipse that would pass over the center of the United States, breaking the 100-year dry spell. I did NOT want to run into the same situation I had at Horseshoe Bend. 

Call Back...In a Couple Years

When I got home I went to Google Earth and constructed a circle. Living in Tucson with family in Minnesota, summers were traveling time, so I put the center of a circle on top of the house in Minnesota where my in-laws lived. For the radius, I drew a line that intersected the center of totality for the 2017 eclipse: Central Nebraska, north of I-80, away from big population centers. Sounded good, so I zoomed in. The little town of Ravenna came into view. Street View showed a nice downtown and a hotel, the Grand View Inn. I called the Grand View and spoke with Jerry, the proprietor of the establishment. He knew nothing of the upcoming solar event, so I gave him the pertinent information and asked about a room. 

"Why don't you try calling back in a couple years, but I'll keep your name and number handy" was his kind reply to my possibly over-eager desire to procure a room ahead of time.

I really did do the circle thing...

I called Jerry back late in 2015, and followed through with reservations and such. He was glad I had called him way back then in 2012 because it gave him a chance to alert the other townspeople of the coming event. Plans were made in the small town of Ravenna, Nebraska for barbecues, movies, games, souvenir booths, a petting zoo, and other events for the weekend in August. Astronaut Mike Fincke, a frequent occupant of the International Space Station, gave a talk at the high school the Saturday before the eclipse. In short, the town pulled together and made a welcoming, positive place for people to come and view the eclipse under the umbra.

Ravenna, Nebraska

My setup for this eclipse was similar to what I used in Page. I scavenged an old ceiling tile and taped the poster board to it. This time around I made plans for my camera. I rented a big lens and made a solar filter out of a sheet of Baader solar film and cardboard that fit into a filter adapter. Astronomical arts and krafts.   

Caption

As the center of the umbra barreled across central Nebraska at 782.9 miles per hour, I was directly in its path.

The sense of community for this eclipse was amazing. People came by and asked if they could watch the eclipse with us, and of course, all were welcome. Many would get close to the projection and take pictures. My telescope, a Dobsonian-type, does not have a motor-driven mount, but rather needs to be pushed or pulled in order to center the image you are observing. People wanting to take a picture would nudge the scope so that the sun's eclipsed image was full on the screen. 

At one point a woman approached and gave her name stating she was a reporter for the Kearney Hub, the local newspaper. She asked me some questions about how the telescope worked and where I'd come from. I got a short write-up in the Kearney Hub that evening. Another pleasure added to the experience. 

Others came up and engaged. Charley found that I had forgotten my camera tripod at home and was limping along with a cheap, flimsy substitute I had picked up on the way to Nebraska. He loaned me his heavy duty tripod for the duration of the eclipse. Uwe, a fellow guest at the Grand View, enjoyed the view and conversation, both of which were grand indeed.

Picture taken in middle of Grand Ave., Ravenna, NE
Grand Ave. - Ravenna Nebraska

As totality approached, I told myself to concentrate on the experience, not on equipment. I succeeded for the most part. I took pictures without the filter on the camera, capturing some of the sun's corona, though there was a thin layer of cirrus clouds that kept the corona just out of reach. I tried to take pictures of my surroundings with my phone, but I was too caught up in the moment, goose flesh coursing over my skin like waves. Venus appeared high in the sky. Street lights came on, but since it wasn't pitch black, they had no effect on the moment. Crickets started to chirp in the grass beside the building. My wife believes she saw a bat come flitting by. The moment of totality was greeted by whoops and cries and clapping from other observers in town. I remember saying out loud something to the effect that I had no words to describe what I was seeing. At the time, two-and-a-half minutes seemed a long time, and I remember at several points stopping just to revel, and know I was reveling, in the moment. 

Then suddenly it was no longer possible to look directly at the sun. Totality was passing. One last picture without the filter on the camera, readjust the telescope, and the event everyone had gathered for had passed. Just like that. Sometimes when something is  over with quickly, people are dissatisfied. That was not the case with totality. The stunning, emotional, fascinating, and slightly mystifying, almost scary experience was obviously deeply felt by everyone. There were no disgruntled eclipse viewers in Ravenna that afternoon. Nature's most dramatic display did not disappoint anyone.

Geek Attack
Geek Attack - photo by Charley Carlin
Eclipse Progression, and Regulus Hanging in There
Eclipse Diamond Ring effect, photo by author
First Diamond Ring - Beginning of Totality Phase