Wow, really of Troy? I've never heard of that before. Is this just a memory statement or do you have a site I can go to, to read up about it. It sounds very interesting and I'd love to know the reason behind it.
well, its a memory statement.. and is there a site? might be one somewhere..
you can make a simple camera obscura, (a large box, lined with black cloth, (or matte black paper) and a small hole. opposite the hole, a sheet of white paper. you put your head in the box, with the pin hole over the back of your head, and the paper in front of your eyes.
then with an adult's help, you can put your back to the sun, and safely watch a solar eclipse.
the cloth helps seal out stray light round your neck (the bottom of the box can be sort of cut to fit).
there have been several solar eclipses in north america (NYC area) that i have seen using a camera obscura.
you look stupid (from the outside) but who cares? you get to see the eclipse, with out going blind!
as for why it works, the pinhole asks as lens (just as we sometimes squint to see better!) and it focuses the light.
One other reason for the cloth (in box camera obscura's) was you could open the box (we used "paper" -the kind that hold ten reams) boxes, with removeable lids.. the heavy cloth allowed you to move the lid (away) to get a better focus.
old black denim was a good choice, (or other semi heavy twill) it doesn't really have to be black, just heavy and dark (to keep the light out)
