News and Views

From my kids accomplishments, to my heretical perspective of the world

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May 21st, 2012 · 4 Comments

Yesterday Derek and I drove up to northern Arizona to view the eclipse. We drove the Volt, but that’s another post.

This was an “annular” eclipse, meaning that the Moon was a little too small to completely block out the Sun as in a total eclipse. Seeing a total eclipse is on my bucket list, but this was still the best eclipse I have seen.

We could have seen the eclipse in Tempe too, but it would have just been a crescent. By driving north we were able to see a full ring, with the Moon completely within the disk of the Sun.

Here’s where we went:


The blue lines indicate the region where the Moon would be seen completely within the disk of the Sun. The red line indicates the line of maximum duration, where the Moon would be centered inside the sun. We were close enough to that middle that it didn’t make much difference visually.

We didn’t have very good optical equipment: A pinhole projector, and camera phones. I tried to buy welding lenses Sunday morning, but of course every Home Depot and Harbor Freight in the state was sold out. Next time I’ll go shopping early! We did meet some other people in the later stages who had eclipse glasses, and it was very cool seeing it directly rather than projected, but I was still unable to take pictures through the glasses.

Here’s what it looked like with the moon about half way in (there are multiple holes of various sizes in our pinhole projector, producing multiple images of varying brightness and clarity):


And here’s at the maximum coverage:


At this time it was noticeably darker and cooler. A half hour before, the sun shining on our bodies was hot and I was wearing sunglasses. At maximum coverage I had to take my sunglasses off, and I could barely feel any heat from sun.

We also had a lot of fun with shadows. The following picture was taken when the sun looked like a ring. Derek and I were standing on a hill casting our shadow on the hill below us. Look carefully in the middle and you can see at least two rings of light in the middle of the shadow. Basically, the gaps between our limbs were acting like pinhole projectors, and creating an image of the sun in the middle of the shadow. Notice too the weird shapes the shadows create, and how the edges are extremely blurred.

Ring Shadow

We noticed another effect as the sun was reduced to a narrow crescent. Normally a shadow is blurry on all edges the same amount because the sun is a circle in the sky and the symmetry blurs the same in all directions. But when the sun is narrow in one direction and long in another, the shadows become asymmetric.

Look at Derek’s arms in the following two pictures. When his arms are extended upper left to lower right, the shadow is fairly distinct, but when they extend from the upper right to lower left the shadow becomes much blurrier (the big rectangle in his right hand is a piece of cardboard).

Shadow Upper Left

Shadow Upper Right

You can also see several crescents throughout the images. Again, projected images of the sun. Notice that the line of the crescents is parallel to Derek’s arms at maximum clarity.

The trip was well worth it for me. I’ve seen 4 or 5 eclipses before, and this one is by far the best so far — it’s the first one where I was positioned to see the moon fully inside the disk of the sun.

But now I want more! People say that on a scale of 1 to 10, a crescent eclipse is a 5, and an annular eclipse is a 9. A total eclipse is a thousand. It is said to be almost religious in its effect on the viewer as waves of shadow sweep across the land, the stars come out and the sun’s corona becomes visible.

There will be a total eclipse sweeping across the central US in August, 2017. I hope to see you there.

Tags: Computers, Tech & Science · Family Updates

4 responses so far ↓

  • 1 Donna // May 22, 2012 at 7:39 pm

    I watched it from here in Mesa, where we saw a slim crescent, but your post makes me want to see the total eclipse in 2017. Maybe we can plan to see it together!

  • 2 Donna // May 22, 2012 at 7:49 pm

    Just took a look at the map, and the GE in 2017 is just a few miles from Rick & Denice’s home. Hope they are up for some house guests!

  • 3 Daryl // May 22, 2012 at 8:58 pm

    The path passes very near Boise too.

  • 4 Donna // May 24, 2012 at 9:23 pm

    You’re right, just a few miles north of the Holsinger’s. It will be a shorter time, but still on the path.