52 lines
2.6 KiB
Plaintext
52 lines
2.6 KiB
Plaintext
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THE HUMBLE TELESCOPE
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David Daye
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Columbus, OH
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A quick, fun telescope project for kids and lazy adults is the
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Humble Telescope, a solar viewer that can produce foot- to yard-
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sized images of the sun, including sunspots down to a few earth
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diameters. And although far simpler than a similarly-named
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instrument, the Humble Telescope may be a more reliable, cost-
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effective way of viewing of detail on a heavenly body.
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Since a pinhole camera works not by refraction but by simple
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geometry, it follows that a tiny MIRROR should create as good an
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image as a pinhole in a lightproof box. The advantage of the
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mirror is that you can shoot its image anywhere you please, into a
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darkened room far enough back to produce big if somewhat dim
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images. You can only do that with a pinhole by making a barn-sized
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viewer.
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As with the Other telescope, the key element here is a special
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mirror -- but this one only needs to be a flat FRONT-silvered one,
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in almost any shape of 1 square inch or more. While you, too, can
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have one specially made by a government contractor, you can also
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pick one up in any shopping mall parking lot, where they are
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produced by the timeless forces of automobile fender-benders.
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The shiny part has to be on top, because the image is ruined
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if light has to pass in and out of glass. Clamp the mirror to your
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camera tripod (kids: stick it on a dry rock with bubble gum). Now
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make the pinhole "mask" that does the actual imaging. Take your
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business card (the gum wrapper) and poke a 1/8" to 1/4" hole with
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your executive pen (rusty nail).
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Open the window of your viewing room--glass, screen and all--
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and block off most of the opening with shades or towels. Go out
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into the sun and use the light of the full mirror to aim the image
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into the room. (Prop your mounting rock into position.) Gently
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tack the mask over the mirror with tape so that only the pinhole
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area is exposed.
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Dash in and watch or photograph at will! Sunspots appear as
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dim smudges that wiggle and move along with the image of the disk.
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You have about a minute before the disk tracks away from the
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window. The farther the mirror from the wall, the bigger but
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dimmer the image. The bigger the pinhole, the brighter but
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blurrier the image.
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For better viewing: 1) Set up a flat, white cardboard or
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screen for the image. 2) Keep the room the same temperature as
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outoors to minimize heat distortion. 3) Keep the room dark as
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possible so as to see more dim sunspots. 4) Have parent or teacher
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do the aiming so you can keep your eyes used to the dark.
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