Part 1 | How I Shot The 2017 Great American Eclipse

Stephen G. Agnew Adventure, How-To, Photography Leave a Comment

“The best laid schemes o’ Mice an’ Men often get laid asunder.”

~ Robert Burns

Full disclosure: I didn’t know that a total solar eclipse was going to happen. WHOOPS.

I kinda feel pretty silly admitting that, but alas ’tis true. My friend Howard made a passing comment about “the eclipse next year”, to which I thought to myself “What the what?” And thus my adventure began.

You see, up until late 2016 I mainly tracked tornadoes and Milky Way visibilities to shoot, along with humans in candid mode in my international travels. But an eclipse? I thought you needed thousands of dollars in telescope gear to do that, so I never gave it much thought. I didn’t fail before I started, I simply failed to consider the possibility of taking that first step. Lead by my curiosity, I purposed myelf to give it my best shot.

As with most challenges that appear impossible though, there’s always a way to make it happen. All it takes is curiosity, an industrious hand, research-itchy fingers, and tenacity.

So I figured that I’d really like to share how I shot the 2017 Great American Eclipse, from when I first heard about it to the turning off of the cameras on August 21, 2017. I think it’ll be a fun little post, n’est-ce pas? So let us journey together!

“The Earth isn’t flat. If the Earth were flat then all of our eclipse predictions, intricately dependent on the mathematics of a spherical Earth, would always be wrong. To the contrary, I was able to observe and track the eclipse’s phases down to the very second in real time—calculated years in advance, precisely because the Earth is a sphere.”

~ Some wee lad

Horcrux #1: Where On Earth Will It Be?!?

The conundrum that rattles your noggin the most when “eclipse hunting” is: “Where is the best spot to be to shoot the eclipse?”

Oh but it can’t be THAT simple, can it? Nope. Even that question by itself is full of complication, because it’s not just a question of what’s the path that the eclipse is going to take over the Earth, but where within that path will you get the longest duration and the maximum obscuration of the sun. THEN, you’re hit with an even bigger problem: What’s the weather going to be like in 8 months? Will the cloud coverage block the eclipse or will it be clear day?

So in solving the first Horcrux of the Great American Eclipse, we have to solve these questions:

  1. What is the path of the eclipse over the Earth?
  2. Where is the center of the eclipse path, giving you maximum duration & maximum obscuration?
  3. What will the cloud coverage be in August, 8 months from now? Will the weather be naughty & block the eclipse?

The honest truth is that questions number 1 & 2 are super easy to figure out, it’s question #3 that’s a bugger. To solve #1 & #2, stronomers across the world—particularly at NASA—have calculated with a precision of within 330 feet where the moon’s shadow will fall on the Earth.

How do they do it? (Scientific history is fun!)

Well in the 21st century scientists first begin with 19th century math developed by German mathematician and astronomer, Friedrich Wilhelm Bessel (1820)—specifically called Besselian elements. Besselian’s math was later improved it in 1855. Besselian elements are pretty much a set of values used to calculate and predict where the moons shadow is going to fall given a localized area on a fundamental plane. This then allows us to calculate the total path of the eclipse over the Earth’s surface. After this path is calculated, scientists project the calculated shadow path onto the Earth’s spherical surface by plugging in the values for the Earth’s rotation, it’s shape (spherical), the observer’s elevation, and the observer’s latitude and longitude.

The anatomy of a total solar eclipse

With the assistance of modern computers a model is created, the complicated calculations are run, and out spits the path of the eclipse shadow over the Earth. To increase accuracy, NASA uses topographic mapping of the moon’s surface done by the Lunar Reconnaissance Orbiter to include the mountains, valleys, and craters on the moon that would let some light through the obscuration of the sun. These mountains, valleys, and craters also create what’s called “Bailey’s Beads”.

Well now, that covers questions 1 & 2…so what about #3?

Ah, good question about the question. The short of it is that you simply can’t definitively answer #3, all that you can do is best guess. Now, this is going to be an informed best guess, not licking your finger and sticking it in the air. You see, there’s a certain pattern to weather from month to month, but pin-pointing the weather on a specific day months in advance is impossible. This is why you have search the historical record for the position on the map that you plan to be on during the eclipse.

Cloud coverage historical data for target location for August 21, 2017

I used several online tools to look at the average cloud coverage for every location, but I settled on the Weather Spark website for my cloud coverage historical data.

This of course begs the question: What’s my target location?

Your target location is going to depend on where the lowest cloud coverage is predicted to be along the path of the eclipse, your roadtrip budget, your tolerance for camping in your car if you can’t afford the $1,000/night Motel 6 rooms, and other variables that differ from person to person. My advice would be to begin with the average cloud coverage map and then plan your target around that. My original target was in Kentucky, but I did some more digging and found that the average cloud coverage was best in Wyoming. So I changed my plans at the drop of a hat for Shoshoni, Wyoming.

Cloud coverage historical data for target location for August 21, 2017
Cloud coverage historical data for target location for August 21, 2017

The below map shows a color read-out of the average cloud cover during August. The closer you get to the cool colors then the less clouds are predicted, and conversely the warmer the colors the more clouds that are predicted during the eclipse. As you can see, Wyoming looks pretty stinkin’ good for having clear skies. My original target of Kentucky? Not sitting as pretty.

Average cloud coverage for August

Another weather map shows what percentage chance you have of having cloud coverage on August 21st during the eclipse. As you can see below, I was at a very welcoming 4% chance of not being able to see the eclipse, which means that I had a 96% chance of seeing the eclipse with no clouds obscuring it. That’s exactly what happened as well.

Specific cloud coverage prediction for Shoshoni, WY on August 21, 2017

The below map gives you another visual of the cloud coverage predictions for the day of the eclipse. As you can tell already, there are tons of resources that you can turn to in order to make sure you’re in the optimal spot for the eclipse.

Cloud coverage historical data for target location for August 21, 2017

Just to give a window into where I was, this was the data for my final target location.

The wonderful thing about choosing Shoshoni, Wyoming was that it was extremely remote in the desert and so I was able to get to my location with no problem of traffic. Of course, the closer you get to the eclipse the more cluttered the highways became, so I left a week before the eclipse to make it there in time. When I got there a few people had already setup camp with their vehicles so I chose my spot away from everyone, pitched my tent, and waited for the time to come.

Campsite in Shoshoni, WY a few days before the 2017 Great American Eclipse

I had a few days until the actual eclipse so I had some time to take some Milky Way photos, along with going into town and testing all of my equipment. I’ll get into my equipment in a future post, but essentially I brought my Sony A7SII with my 18mm Carl Zeiss Batis lens, and rented a Sony A7RIII with a 400mm Sony G-Master lens.

Milky Way shot the night before the 2017 Great American Eclipse in Shoshoni, WY
Camera gear to shoot the 2017 Great American Eclipse, Sony A7SII and A7RIII

The below Google maps give you an idea of where my target location was in more detail. I’m not a big fan of snakes, so I was pretty thrilled when I only saw one snake, and he popped up his head before my care went over him. Whoops.

This difficulty of choosing your target location with cloud coverage in mind is actually a reality that vexes me for the 2024 total solar eclipse that passes through my backyard of Texas (literally 60 miles to my south). The 2024 eclipse is in April, which is prime storm season here and so visibility is going to be extremely challenging.

Moral of the story:

So be flexible in your target choice and consult a cloud coverage map that shows the average historical data for each day of that month. After you choose your target location, you have more Horcruxes to smite. We’ll cover those in “Part 2” next.

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