A couple of schemes for safely viewing the sun's projected disk: 1.) Use a small piece of ordinary looking glass as a "pinhole" to project the image onto the shady side of a building or other screen. (This is a sort of, 'steerable shadow-sharpener.') Holes of various sizes can be made in pieces of card or thin metal (container stock,) and taped to the bit of mirror to select optimum size for the particular setup. If mounted on a camera tripod head, it is easy to aim the mirror to image at a convenient viewing location. The .5° diam. image will project at about 1:120, ratio, so at mirror to screen distance 10 ft., the image is about 1 in. across, at 20 ft. it is 2in., etc..
2.) Use a small telescope in eyepiece projection. This can be half of a pair of binoculars or of Galilean opera or field glasses. Mount the glasses on a piece of wood, and arrange a shadow-producing screen (e.g., a piece of heavy cardboard) with a hole to allow sunlight to enter only one objective lens. Arrange a matte-white surface perpendicular to the axis of the corresponding eye piece, to receive the exit beam. For a 7X35 binoc., at 20 in. (50 cm.) from the ocular, the disk image will be about 1.22 in. (31mm) across. Greater distances will, of course, yield larger images. You can quick-check that your glasses have sufficient range of focus by standing facing a sunlit white surface, with the glasses tucked under your arm. Your body should shade the target area, but you should be able to position things so that a white circle is projected within your shadow. (Or two circles, if both objectives are exposed.) Adjust the focus until the disk is as sharp-edged and color-free as possible. Again, if mounted on a tripod's universal-head, the board, with glasses, shading-screen, and projection-screen attached, can conveniently be moved to aim the setup at the sun. WARNING! If you employ this second method, you must be vigilant, so that no one attempts to view the sun by looking through the eyepiece. Old-timer Bill
