Tuesday, October 31, 2023

An annular solar eclipse

Annular Solar Eclipse in Progress, Capitol Reef National Park, Utah

October is a month for all things spooky, so in some ways it’s only fitting that earlier this month I got to witness an annular solar eclipse, a celestial event that for a fair amount of it the sun resembles a sickle.

Before I talk about the experience, I’ll provide some background on solar eclipses, since sometimes materials on this site are used for educational purposes. If you don’t need an intro to eclipses, feel free to skip down to the next bold heading.

During a solar eclipse, the moon passes between us and the sun, blocking at least part of the sun’s face. They’re actually fairly common. Every 18 months or so, a total eclipse is visible somewhere on Earth. In a typical year, there could be as many as five eclipses where less of the sun’s face is obscured.

Most of these lesser eclipses are known as partial eclipses. In these, from our vantage point, the moon’s path cuts through one side of the sun as opposed to the center. At their peak, the sun looks like the crescent moon.

In an annular eclipse, such as the one I saw this month, the moon crosses through the middle of the sun. It just isn’t large enough to completely block it. At its maximum, a ring is visible around the moon, which is why these eclipses are also known as the ring of fire.

Why is it that sometimes the moon can completely obscure the sun, but other times the sun is visible around the moon’s edges? The moon’s orbit around the Earth is not a perfect circle. In a total eclipse, the moon is closer to us and therefore appears larger in the sky. When you hear the term “supermoon” on the news, that’s just a full moon when the moon is closest to Earth.

During the annular eclipse this month, however, the moon was 248,000 miles from us — almost as far away as it ever gets from us. (Its closest approach is 225,623 miles away.) At this eclipse's maximum point, when the moon appeared within the sun’s face, almost 10 percent of the solar disk was still showing.

Annular Solar Eclipse at Maximum, Capitol Reef National Park, Utah

My first annular eclipse
Even though it wasn’t a total eclipse, I think it’s something that’s still worth seeing. I saw my first annular solar eclipse in 2012 from Lassen National Park in California. A small group gathered at a roadside pullout, watching the moon slowly advance across the sun’s face.

When that eclipse peaked, we all marveled at the odd shadows on the ground. The sun’s light is a ring, not a point, so the edges of the shadows are much softer. Some thin branches fail to cast shadows entirely.  The maximum effect lasts but just a few minutes, so I thought it would be fun to make the effort to see another annular eclipse.

Temple of the Sun with Annular Solar Eclipse, Capitol Reef National Park, Utah

A poetic setting
During my first annular solar eclipse, I spent much of my time shooting detailed pictures of the sun. I wanted a nice image of the ring of light. For this attempt, however, I wanted it as a component of a landscape.

You never know if the weather is going to work out, so I had a couple of concepts in mind. The strongest — and it turns out the only one where the clouds cooperated — was to photograph the eclipse from the Cathedral Valley in Capitol Reef National Park, Utah. It’s my favorite part of that park. Giant sandstone monoliths jut out of the ground. And for this purpose, two of them had appropriate names: the Temple of the Sun and the Temple of the Moon. My plan was to photograph the eclipse between the two of them.

That part of my plan didn’t quite work out. On my previous visit there years ago, I didn’t remember seeing smaller rocky mounds in the area where the temples and eclipse would all line up. The mounds, while small, would have blocked the view of the smaller Temple of the Moon. And if I got closer to the two temples, putting the mounds behind me, I would have had to use such a wide-angle lens that the sun would have appeared to be a tiny dot in the sky even at maximum eclipse. I adapted, and decided to photograph the eclipse just over the more prominent Temple of the Sun.

It took two exposures
What’s hard to appreciate is exactly how bright the sun is. During a total eclipse, it really does start to feel a bit like night. But during an annular eclipse, even though much of the sun’s face is blocked, it still feels very much like day. The sun was too bright to look at with the naked eye and was too intense for a camera to capture at the same time it’s recording the much dimmer landscape.

For this image, I made two separate images that I later combined in Photoshop. I took one picture of the sun. Then brightened the exposure and took a picture of the landscape. This task was made a bit easier by a band of thin clouds that had moved overhead. They dimmed the eclipsed sun a bit so that I had less dramatic contrast to overcome.

Composite images are not my style, but it was the only way to show the experience in a single frame.

Annular Solar Eclipse in Progress, Capitol Reef National Park, Utah

The texture of the moon
While the eclipse with the Temple of the Moon was the one image I wanted to make this time, I still appreciate that these events give you a different view of the texture of the moon. We know that the moon’s surface is rough and full of craters, but it’s during these eclipses that you can see the peaks and valleys that run around its edges.

Consider this image, which shows the moon moving away from the sun. If the moon were a perfect circle, there would be exactly one point where the ring of light was broken. But it’s actually broken at several different points, allowing us to see those peaks and valleys. And considering how far away the moon was, those must be some impressive mountains.

(Prints of Kevin Ebi's images are available through LivingWilderness.com. Learn about new work by joining his mailing list.)

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