Our Partial Eclipse

May 27, 2012

Last Sunday morning MM came into the room with an old shoe box in her hand.  She asked me if the box and a piece of aluminum foil would make a useful pinhole camera.  I thought it might, Wonderful Ones, but my wife does not usually take on DIY experiments and I was very curious to know what her project was about.  She said an eclipse was coming up and she wanted to put together a “camera obscura” in order to be able to see it safely.  I hadn’t heard this interesting news, and after a confused conversation about whether it was a lunar eclipse (at night) or a solar eclipse (during the day), a quick look on the Internet told us that, indeed, a (solar) eclipse of the sun would occur in the afternoon.

According to a map on one website, the heart of the shadow created by the moon passing in front of the sun would sweep across far Northern California.  It appeared that near places like Crescent City and Mt. Shasta one would be able to see a total eclipse and the famous “wedding ring” effect produced when the dark disk of the moon is perfectly outlined by solar fire.  From our vantage point in the Bay Area, though, the eclipse would be only partial.  I figured for us the moon would appear to bite off only a small piece of the sun’s visible surface, and most people going about their day might not even notice it was happening.  Still, an eclipse of any sort is an exciting phenom and I wanted to see it too.

MM made a tiny hole with the point of a pin in a piece of aluminum foil.  When she held this up to the bright sun with a  white card placed behind in it’s shadow, a miniature picture of the sun was projected though the hole onto the cardboard.  This proof of principle showed the pinhole camera idea would work, but it also revealed that the image would be so small –only the size of the head of a pin– that it could not be seen well.  Of course, looking directly at the sun is an absolute no-no unless one wears a welder’s helmet or some other extreme eye protection which we did not have.

I tried to think of a better way to be able to see the sun.  Pulling a dusty photography tripod out from under our bed and my binoculars out of the hall closet, I attached the two.  Then I clipped a square of white cardboard to a wooden rod and fastened the rod to the binoculars with rubber bands.  Finally, I cut a round hole in a larger piece of cardboard and fitted that around one lens of  the binocular.  Viola!, when this contraption was pointed at the sun  it projected a beautiful, clear picture of our star onto the cardboard target.  The image was about the size of a quarter and it was so sharp one could even see half a dozen black dots–sunspots!–scattered across the surface of the sun.  I had a dark red photographic filter the right size which I placed on top of the “monocular” lens in order to reduce the brightness of the image.  Now, the sun projection was a dramatic scarlet and completely safe to view with the (actual) sun comfortably at one’s back.  Cool!

So, about mid-day we set up our  new Solar Observatory in the driveway and waited for the eclipse.  It was such a beautiful day.  The sun was warm, there was a light breeze off the ocean and the sky was blue and utterly clear.  As the afternoon progressed we checked the Observatory every few minutes while doing other things around the house and garden.  Always the sun was there, round and red as a freckled plum with no hint of the moon moving in to take a bite of it.

All afternoon we watched the sun, repeatedly adjusting our rustic Observatory in order to track ol’ Sol as it moved imperceptibly down the sky.  We were having fun, but we were impatient too.  Where was the eclipse?  Was it possible, we asked, that those astronomers got it wrong like weather forecasters sometimes do?  Checking the Web more deeply, I read that the event would be seen LATE in day and into the early evening.  Oh, OK.  That was still fairly vague,  but we didn’t have any other plans and luckily the ocean fog which often rolls in at the end of a warm day was nowhere in sight.

At last, sometime between 5:00 and 5:30 I checked the Observatory again and saw that a piece of the sun was missing on it’s right edge, as if it had been snipped out with sharp scissors.  The moon had arrived!  For an hour we watched as the snippet grew into a larger and larger half-circle of darkness across the face of the sun.  Meantime, the sunlight shining on our bit of the landscape was changing too, although the effect was subtle.  Somehow, the light was still intense but there wasn’t as much of it.  It was bright and darker at the same time, which is different than when a cloud passes across the sun.   A clearcut transformation, though, was that the shadows cast by tree leaves had become exotically,  beautifully crescent shaped.

                                                                                                                                                                                   

At a certain point, with about two thirds of the sun hidden, it was plain that the moon was not passing BY the sun but was advancing to the left directly across it.  On this trajectory it would soon cover the entire sun.  Wow….the astronomers MUST have gotten it wrong, I thought.  We were about to experience a TOTAL eclipse. We were going to see the spectacular Ring of Fire, baby!

But, slowly, slowly the dark half-circle seemed to pause and then, as if it had gone into reverse gear, the moon backed up and moved to the right–the way it had come in–and the crescent of bright sun grew infinitesimally bigger and bigger.  It was a perplexing phenomenon and I still don’t get it.  It must have had something to do with our viewing angle relative to the sun and moon increasing (as our spot on the earth rotated away from them) faster than the moon was actually moving across the sun.  Whatever the cause, the astronomers were right, we were seeing a partial eclipse only (although a more stunning one than I had expected) and now the show was coming to a close.  I watched for a while longer using both sides of the binocular to project sun images, but this seemed less magical than the original setup and I ended up playing silly Eclipse Party games.

As the late afternoon light returned and the wonderful crescent leaf-shadows faded, I disassembled the Solar Observatory and put it back in the closet and under the bed.  Light cocktails were served and dinner was ready.  It had been a great day puttering about at home and watching the sun as it moved across the blue sky.  I thought green growing things must “watch” the sun too, attending every moment to it’s location and how much energy it is beaming onto their leaves.  Wonderful Ones, I felt that like a plant I had had a relationship with our Sun on Sunday.  I felt a definite glow….although possibly that was my lack of sun-block talking.

–NeRP

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2 Responses to “Our Partial Eclipse”

  1. LOVE this story!! The red sun on the black card is stunning, as are the photos of the crescent shaped shadows. xo

    • nerponline said

      I’m so glad you liked it. Someone said that eclipse was a once in forty years event here in NorCal. We were very lucky to have perfect weather for the event, and convenience of a weekend too!

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