(Editor’s note: Soon to be Photofocus author, Steve Inglima presents a post on his experiences photographing the solar eclipse of 1991.)
Back in the days when I was the technical manager for GMI Photographic, which marketed among other things Bronica Medium Format and Sea & Sea Underwater cameras, on my way back from a DEMA (diving industry) show in Las Vegas our fight was oversold; and I took a bump to earn a free ticket. My first impulse was to use that ticket to travel with friends and dive at Grand Cayman Island. But then I read about the big eclipse that was to happen across the Pacific and peak on the western coast of Mexico. I decided I could dive anytime, but I should journey to Mexico as this was to be the “mother of all eclipses” in my lifetime. What made this one so rare, and in fact, all of them special, is that they’re not common.
What is a Solar Eclipse?
In technical terms, when the moon is close enough to the Earth and in a precise position, it will block 100% of the sun’s direct appearance. This is called a total eclipse, or one having a magnitude greater than “1”. There are annular eclipses (magnitude less than “1”), total eclipses, hybrid eclipses (ones that change type during their progress and resulting location), and partial eclipses where the moon shadows only a part of the sun’s disc. Depending on the celestial mechanics, a total eclipse can occur for a few seconds in a very narrow band or even a point on the surface of the Earth, or extend great distances as the Earth rotates and the moon revolves around us at the same time. The maximum theoretical time for totality is 7 min 32 s. This value changes over the millennia and is currently decreasing. By the 8th millennium, the longest theoretically possible total eclipse will be less than 7 min 2 seconds. No, Al Gore; this is not due to “global warming” :-).
Why is the upcoming eclipse so special?
Within some of our lifetimes, we could have seen the big one in the Indian Ocean on June 20th, 1955, with a totality of 7 minutes, 8 seconds. There will not be another one that long until June 25th, 2150!!. That’s what made the July 11th, 1991 eclipse so compelling to experience, with a magnitude of 1.04 and a time of totality at the maximum point of 6 minutes and 53 seconds. Rare indeed. Traveling to Mexico was a little easier in 1991 than it is today of course, with all of today’s restrictions on weight and security and all. The closest airport to the eclipse was in Puerto Vallarta, so off I went through Mexico City. I packed a Bronica SQ-A (6x6cm 120 roll film camera) and a 500mm lens along with my home made mirrored mylar filters for safety (more on this later). I wasn’t sure how much I was going to see and from where I was going to see it precisely. I went like a dharma bum hoping to simply absorb the experience. Swimming in the hotel’s endless pool on the 10th of July, I just happened to discover that there were around 10 like minded Americans who were there for that same experience. We all agreed it would be cool to travel together to wherever the great totality would be. The hotel arranged for two vans for us; our newly formed group chipped in to pay for them. We planned to meet at around 4 am or so. As it turned the evening was replete with a false fire alarm around 3 am… so, not a great night for sleep. I’m not a morning person, to begin with. Off we went on a fateful day, slogging through two lane roads for 5 or so hours. Our destination was Tuxpan (a seeming microscopic agrarian community near the west coast). The viewing was not looking too good. Clouds were persistent and while the sky was in flux, it was hot and humid and it looked as if it could rain. We were near the Tropic of Cancer, and it was just after the summer solstice….so it was effectively like the equator to us and felt like it. The two vans had CB radios. We took turns in trying to find a good viewing field. Our van’s group set up in one farmer’s field, which attracted a pickup truck with a few guys armed with AK-47’s wondering what we were up to. Fortunately, our guides could explain in Spanish about our appearance there with the tripods, cameras and very long lenses. Then the radio call came into our group that, while with only 15 minutes to spare or so, the other group had found a pretty good field with a clearer view! We packed everything up and off we raced to the other farm. We just made it. Then we set up again; cameras on tripods, lenses with filters on the cameras. We marveled at the decreasing light, the strange appearance of shadows on the ground (the sun becoming a point light source, so everything within sight of the sun produced PERFECT finely detailed shadows. Then, Bailey’s Beads…the rays of the sun kissing the threshold of the moon’s mountains and topography, making irregular pinpoints of light at the junction of the sun’s rays and the moon. Finally, totality. It was pretty dark. Stars appeared. I burned through three loaded magazines and had trouble finding more film in the dimness. I have to confess that equal to the visually amazing experience was what I heard. Birds grew eerily silent. Cows, however, started bellowing as they headed back to their barn, confused about the timing of the apparent end of day. People in our party sounded in various states of ecstasy. It was a magical, mystical shared experience. Then, after the 6 minutes and 53 seconds, the first ray of the sun, the “diamond ring” appeared, another of Bailey’s Beads. It was simply….mesmerizing. Many of the group had already been eclipse chasers, traveling all over the Earth’s surface when another would appear. We are lucky, in that we in the US will not have to leave the comfort of our borders to see the total eclipse this month in August 2017! What is about to happen in the US is rather spectacular for a couple of reasons, not the least of which is that it’s path travels completely across the United States. It starts in the Pacific east and south of Alaska, and ends approaching the coast of Africa, with maximum totality in Kentucky. And, lucky me…totality will literally pass right over the house I’m building in North Carolina!
Beware of the sun!
You’ve read about the precautions you absolutely must take to protect your vision and your camera gear. With the exception of the 2 minutes+ of totality, you will need to guard anything that “sees” with a filter that blocks most of the light of the sun. Consider a filter with an ND value of at least 5.0, which blocks 99.99% of the photons coming from the sun. ND 5.0 is equivalent to 16 2/3 stops. ND values are logarithmic like deciBels, in that .3 = 1 stop, .6 = 2 stops, and so on. Basically, multiply the desired ƒ stop value x .3 to achieve the desired ND value.
Protect your eyes!
Importantly, the filter needs to block light in all relevant parts of the electromagnetic spectrum, especially UV. Keep in mind that your retinas will “sun” burn just like your skin… Remember that the filter is now part of your optical system. No matter how much money you’ve spent on your lens, it’s reduced to the quality of the filter when its in the optical path. Your filter needs to be really, really flat…and the longer the focal length of the lens, the more this will be a factor. Consider all brands but check with the manufacturer for the specs, or a retailer like B&H for sizes and availability. Marumi 77mm DHG ND-100000 Solid Neutral Density 5.0 Solar Eclipse Filter is available from B&H. It’s been recommended that any viewing of the sun, whether through a camera, binoculars, or even the naked eye be done through a metallized filter. It’s spectral character covers all of the bases. I would recommend reading a bit about it before you make a purchase. Here’s a link for suppliers of solar viewing items.
(Editor’s note: Steve will be back tomorrow premiering his new Tech Corner column on Wednesday. This week’s Corner finds him doing a deep dive on lens selection for the eclipse… and more!)