David asked us to post our eclipse-viewing solutions. Here's mine.
I've got official Eclipse glasses. However, I'd like a bigger image
during the partial phases of the eclipse, and not have the hassle of
constantly taking the eclipse glasses on and off. I'd already
successfully tried using a very good pair of binoculars to project the
sun's image, handheld, onto a white piece of cardboard. But I want to
use those binoculars for totality.
Fortunately, I found a pair of cheap 8x21 Chinese binoculars at the back
of my closet. The two oculars are slightly out of alignment with each
other, resulting in double vision when used as binoculars. But either
side works OK as a monocular, with a bit of orange-blue chromatic
aberration. I thought they would work for this purpose. So...
I mounted the binoculars on the quick-release plate of my tripod using
high-tech rubber bands from the bottom of my desk drawer. I made a
cardboard shade by cutting up an equally high tech box from "Crate and
Barrel," traced the rear barrels of the binoculars, and cut the holes
out with a box cutter. I took another piece of cardboard from the same
box and placed it on my trusty music stand. I aligned them roughly by
putting the music stand in line with the tripod's center column shadow.
I "capped" one side of the binoculars with some masking tape. A bit of
up-and-down and side-to-side, and I had an image.
Here's a side view of the optical end of things, with Katya looking on
in the bokeh:
<http://gallery.leica-users.org/v/pklein/album170/P8140232.jpg.html>
Here's the sun-side view of things. You can see part of the sun's image
on the music stand at right rear. The extra hole (plugged up) on the
shield happened because I first traced the binoculars spread out, but
they would only stay on the quick-release plate when folded up.
<http://gallery.leica-users.org/v/pklein/album170/P8140233.jpg.html>
And here's a better look at the sun's image, partially "eclipsed" by the
outer branches of a Douglas Fir in my neighbor's yard. It was a hazy
day, so I suspect the image will be better in full sunlight.
<http://gallery.leica-users.org/v/pklein/album170/P8140234.jpg.html>
One essential piece of equipment not shown is a piece of dark cloth or
towel to drape over the binoculars when not viewing. This avoids cooking
the optics, which could lead to separation or breakage. Another possible
way to avoid this problem is to alternate oculars every few minutes,
capping the unused rear lens.
The binoculars project an image just like your camera lens does, upside
down and backwards. The farther away you move the "screen," the bigger
(and dimmer) the image is. The binoculars need to be focused for the
sharpest image. I'll replace the blue masking tape with black
electrical tape or duct tape for the actual event.
These pictures were taken very quickly because it was the end of the
day. But I'd say today's dry run and proof of concept went very nicely!
--Peter
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