Witnessing the Total Solar Eclipse of April 8, 2024

I invited my family to see the April 8 eclipse, and we found a place on a bay in the St. Lawrence River.

We had ourselves a grand little reunion up there on the Canadian border, and a great couple of days together. And we got to see a total eclipse, a first for each of us.

We had a dramatic view of the Moon's shadow rolling in and out. Clouds came in just before the eclipse, dimming the Sun considerably and sometimes blocking it altogether, but we got a glimpse of the solar corona.

Venus is visible in the video below after the 3-minute mark, but we never saw the "Devil Comet" Pons-Brooks, Jupiter, or any other planet or star.

We had about three minutes of totality.

It got cold! I had to get some long sleeves before totality, but went back to bare arms soon afterwards.

Someone howled at the Moon's shadow, and we howled back.

Totality is much darker than you see in virtually all pictures and videos, including ours. When I turned around to film the people and houses on the shore, everything was clear in my video, but the shore was almost pitch-black to my eyes.

You can hear the local geese going nuts. Or maybe they were asking themselves scientific questions and coming up empty. "Yo, Lucy, I really shouldn't have flunked out of those high-school science classes. Honk! Now it's coming back to bite us in the butt! Honk!"

The sight of a blue shadow rolling toward us was eerie, thrilling, majestic, but beautiful most of all.

Why Was the Shadow Blue?

Now, here's where I need some help, from meteorologists or astronomers who may know.

Why was the shadow blue, I wondered. We hear about the Moon casting a black shadow upon the surface of the earth. I expected that in overcast skies, the approaching shadow would make the clouds progressively turn black, not blue.

But I've been looking at footage of clear-sky eclipses, and you can see the shadow advancing in a blue sky, as a waxing wall of darker blue. I assume that's because the atmosphere scatters blue light as always, even if a column of air directly in the Moon's shadow is dimmer blue. I suppose it's similar to standing in the open sun under an umbrella: light is scattered by the air, so I don't disappear in a black hole under the umbrella.

While we waited for our eclipse, we had almost complete cloud cover, so I thought the wall of blue approaching from the horizon was simply a wall of cloud that was somehow turned blue by the shadow. But reviewing my photographs, I can see that there were holes in the cloud cover, whereas the shadow was a solid blue.

Someone let me know if I'm wrong, but I think what I saw was the darker-blue light under the "umbrella" (umbra) of the Moon. In short, I wasn't seeing the black shadow that can be seen on the surface of the earth or on the tops of the clouds, I was seeing the column of atmosphere darkened by the Moon blocking the Sun.

I snapped the following photograph ten minutes before totality, at 3:13 pm. I could be wrong but I don't think any of the blue patches in my picture are part of the Moon's shadow.

At that point, the advancing edge of the Moon's shadow would have reached a point on the Earth's surface still 375 miles distant from where we were in Chippewa Bay, New York (offscreen to the northeast in this screenshot):

(double-click this screenshot to see the full video)

Doing some rough research online, it seems that from 375 miles away you wouldn't be able to see even the highest possible clouds.

The picture below was taken two minutes before totality, at 3:21 pm. At that point, the shadow was about 85 miles from our spot (marked by a white arrow in the screenshot). I think the blue at the horizon is now the Moon's shadow.

This is how things looked at 3:22, and we now definitely have a shadow:

Just before totality, a screenshot from my video:

I've never witnessed a clear-sky eclipse so I can't compare, but I'm guessing that the above wall of blue is something you'd see in any eclipse, but the clouds, on a clear day, would be light-blue sky. It would be a contrast between dark-blue and light-blue, as you can readily see in public footage. What a cloudy day apparently adds to an eclipse is this dramatic contrast between deep blue and fluffy white.

Those clouds are white, of course, because they're illuminated by normal daylight, but they seem to disappear when the Moon blocks sunlight.

Totality arrived for us at 3:23 --

Incidentally now I understand why the the front edge of the shadow came toward us looking like a horizontal line that ascended from the horizon, yet three minutes later the back edge of the shadow passed over us from right to left, as you can see in this short timelapse made by Maddie Rosero at the end of totality:

I've seen this contrast in many eclipse videos. The reason is that the ball of the Moon's shadow becomes distended as it glides over our globe. If the shadow is at the equator, at local noon, the sun is directly overhead and the Moon's shadow falls on Earth almost like a perfect circle, but it will become stretched into an irregular shape when it falls nearer to the poles or to any part of the Earth's sunlit face that is about to turn into, or emerge from, nighttime (the terminator line). A person standing in daylight at sunrise or sunset will cast a long shadow in the same manner, just as a person will do who is standing at the "top" or "bottom" of our planet at the poles.

In short, the Moon's shadow was already an irregular oval when it reached us.

Look at the white arrow in the screenshot above. We were waiting there, on the white line marked "3 min", facing southwest. You can see how that white line intersects with the outer edge of the advancing edge at *roughly* ninety degrees, close enough to make it look like a horizontal line at the horizon.

Now look at the white arrow as totality ends (3:26 pm), in the screenshot below. The white "3 min" line there intersects the back edge of the ball at a greater angle, closer to 45 degrees. For anyone standing at the arrow, light arrives first to the north of that line (to our right, in the video), and moments later arrives to the south (to our left). Hence, we saw what appeared to be a black shadow in the clouds moving from right to left, and daylight filling the sky from right to left.