PHOTOGRAPHING THE SUN.

New Zealand Times, Volume LI, Issue 8524, 2 November 1888, Page 3

PHOTOGRAPHING THE SUN.

Mr J. C, O’Loan, of Liverpool, writes : While experimenting with a ray of sunlight in a darkened room I had my attention directed to pinhole pictures, and am of the opinion that startling results can be obtained in photographs of the sun or moon in this way. In a room darkened by blocking up windows with thick paper, make a small hole in the paper with a ‘ darning needle,’ so as to admit a ray of direct sunlight ; hold a piece of white paper in the path of the ray 12in from the hole, you will have an image of the snn Jin. in diameter, at 4ft. an image of 4in., and at the distance of Bft. from hole a lin. image, and so on. The size of opening used as lens does not alter the size of image at any given distance, but only its sharpness and brightness. Say the opening is l-16in.« and gives a sharp picture at 4ft., by enlarging the opening to the size of the image at 4ft. would be still the same but unsharp, so that the screen or plate must be removed to twice the distance to obtain equal sharpness. In a room 100 ft. long a 12in, picture of the sun could be had, and of the moon one very much larger. A series of pipes 100 yards long for camera would give a 3ft. photograph of the sun ; in fact, there is no limit to size of image but the length of camera. Perhaps someone who has more time and space at his disposal than I have may take the subject up.— English Mechanic.