Eclipse

Solar Eclipse taken by shooting through a couple of layers of old photographic negatives, just for fun. The thin sliver of sun is still enough to overpower the image sensor.

The eclipse was a little odd. I live maybe 50 miles north of where there was a total eclipse. Here the moon blocked out all but a little sliver of the sun. It didn't get dark, at best is was a little dimmer than full sunlight. My neighbor noticed that it was a little cooler. I didn't notice any temperature change, but then I don't pay much attention to temperature until I start to get uncomfortable. It was like 70 degrees here and if the eclipse caused the temperature to drop five degrees that would have been 65, which would still be comfortable, so for me it wasn't worth noticing. That's one of the benefits of carrying around an extra 50 pounds of fat.

Illuminated house number. Barely visible here, but it was bright enough to catch my eye.

A neighbor across the street has an illuminated house number that comes on when it gets dark. Well, presumably it comes on when it gets dark. I never noticed it before. But when the moon obscured most of the sun the light came on and when the eclipse was over the light went off. So I'm guessing that for the light sensor, it was getting dark.

Dustbury's post got me to wondering why the moon's shadow was traveling eastward when the sun is traveling westward (the sun rises in the east. Daylight advances ever westward across the face of the Earth).  A little math confused the issue even more. As simple as this problem ought to be, it took me several trials before I finally figured out what my model of this situation should look like.

Graph of Speed and Distance
Bottom scale is minutes
And yes, it's just a coincidence that the bottom scale is 400 minutes long.
Spreadsheet with Calculations

Consider the Earth and Sun as fixed, unmoving objects. The Moon passes between them and since the Sun, for all practical purposes, is infinitely far away, the shadow as it passes over the Earth is traveling at the same speed as the Moon. Imagine driving your car south near sundown, You and your car are going to cast a shadow to your left. The shadow is traveling right along with you. If you maintain 60 MPH, your shadow is going to maintain 60 miles an hour.

However, since the Earth is a ball and not a disk, this speed is only going to be seen when the Moon is is directly inline between the Earth and the Sun. Before the Moon starts to come between the Earth and the Sun, its shadow is simple traveling across space. When the Moon's shadow first impacts the surface of the Earth, it will be at a tangent, so its speed is infinite. As the shadow passes over the Earths surface, that surface will start turning more toward the sun and more at an angle to the shadow. By the time 40 minutes has passed it's speed has dropped to 2,000 miles per hour.

But the Earth is turning. At the equator that speed is about 1,000 MPH. Now we get to the rotation part. The moon goes around the Earth in the same direction that the Earth turns. Looking down on the Earth from above the North Pole, we see the Earth turning in a counter-clockwise direction. The moon is like-wise turning in the same counter-clockwise direction, but the Earth is turning much faster than the moon is going around. So if we were projecting the moon's position onto the Earth, we would see it move Westward, because the moon is slow moving and the Earth is turning underneath it.

The moon's shadow it traveling at the same speed as the moon (about 1200 MPH), which is just slight faster than the surface speed of the Earth, so as the Moon passes in front of the Earth, it is traveling just slightly faster than the surface of the Earth, so its shadow, the eclipse, moves from West to East.

1973 Concorde Eclipse Chaser
(Warning: autostart video)

So the speed of the eclipse depends on the time of day. If it strikes your area in the early morning or late evening it is going to be cooking along and you are going to need a supersonic jet fighter running on full afterburner to keep up with it. If it is during business hours, you could keep pace with a twin engine prop plane. I looked for some indication that NASA or the Air Force or someone had sent up a supersonic chase plane, but the only reference I found was for 1973 when somebody managed to commandeer a Concorde to record the eclipse.

Some commercial airlines arrange special eclipse flights.

P.S. All my calculations were done presuming the path of the Eclipse was over the equator. To more accurately model this eclipse, you would need to  factor in the latitude, which is constantly changing because apparently the orbital plane of the Moon is at an angle to equatorial plane of the Earth.