Kepler also was the first to give a sound theory of vision. (Recall the shot-from-eye or shot-from-object schools of the ancients.) Kepler stated, “Seeing amounts to feeling the stimulus of the retina which is painted with colored rays of the visible world. The picture must then be transmitted to the brain by a mental current and delivered at the seat of the visual faculty.” That is a rather good definition even by modern standards. Kepler, however, was not 100 per cent correct. He held that light had an infinite velocity. To Kepler goes the credit for being the first correctly to explain after-images, a knowledge of which is so vital to understanding how the illusion of motion is created.
Kepler started to use a telescope about 1609 and through its use he was able to develop improved ideas for the room camera by the time he published his Dioptrice, “Concerning Lenses,” a foundation of modern optics, in 1611. In that work the basis was first established for what was later to be long-range or “telescope” photography which makes possible many important effects in the modern motion picture.
The telescope, the most highly developed lens system and the reverse of a projection arrangement, was invented in Holland in the early part of the 17th century. Galileo, who with Kepler did much to popularize the telescope, admitted that he had seen one made by a Dutchman before he fashioned his own.
The name “telescope” was coined by Damiscian of the Italian scientific “Academy of the Lynxes,” to which Porta also had belonged. The invention of the telescope is commonly credited to “the spectacle maker of Middleburgh,” usually identified as Hans Lippershey. The compound microscope, effects of which had been indicated by Roger Bacon, evidently also was invented a few years prior to the telescope—by Zachary Janssen, in Holland. But it was first described in Italy. Early telescopes generally followed the model developed by Galileo, while by the middle of the 17th century the superiority of Kepler’s method was recognized and larger and more powerful telescopes were possible. In recent times the telescope has reverted to a mirror—or Burning Glass—reflecting system instead of the standard style refracting telescope.
To a contemporary of Kepler goes the acclaim for being the first to use the camera obscura apart from a room; in other words, in a portable form. Thus was the first portable camera developed more than two hundred years before photography was invented. The man was Scheiner, another astronomer.
Christopher Scheiner, a German Jesuit, born about 1575 in Swabia, did much work in astronomy and perfected various ingenious optical instruments. Some say he was the first to use the camera projection device for throwing the sun’s image on a screen in order to study its details. This replaced a system which used colored glasses. Kepler, prior to this, suggested the method but it is generally acknowledged that Scheiner made the first application. In 1610 Scheiner invented his Pantograph or optical copying instrument. In March, 1611, he observed sun spots. His superiors were afraid that he and they would be exposed to ridicule if he were to publish such a discovery under his own name—it was so opposed to the contemporary scientific as well as traditional scientific belief. And so his findings were published in 1612 by a friend, under an assumed name.
Scheiner was a believer in the need for accuracy in experiments to form a firm basis for future development of theory. He studied the eye and believed that the retina was the seat of vision. By the year 1616 he had so attracted attention of scientists that the Archduke Maximilian invited him to Innsbruck. Scheiner taught mathematics and Hebrew and continued his work in optics. He was the author of Rosa Ursina,—1626–30, the standard work on the sun for generations. In 1623 he was a professor of mathematics at the Roman College, where Kircher fell under his personal influence. The last years of Scheiner’s life were spent at Neisse in Silesia, where he died in 1650.
Scheiner was influenced by François d’Aguilon, the first of several Jesuits who made an important contribution to what was to be the modern motion picture. D’Aguilon advanced the knowledge of optics throughout Europe.
D’Aguilon was born in Brussels in 1566 and after entering the Jesuits in 1586 and being educated he became a professor of philosophy at the famous college in Douai, France. Later he was head of the College of Antwerp. D’Aguilon did not confine his interests to philosophy and speculative knowledge alone but was very much interested in certain sciences, notably optics. Moreover, he was a practicing architect and probably designed the Jesuit church at Antwerp.
His work on optics, published at Antwerp in 1613, was famous. In it is found for the first time the expression “stereographic projection,” which has survived to the present. This was known from the time of Hipparchus but had not received a permanent name until it was given by d’Aguilon, to whom must go part of the credit for the name of all devices with “stereo” somewhere in the title. D’Aguilon explored at length the subject of after-images. He correctly pointed out that the image physically disappears when the cause is removed (as a camera no longer “sees” after the shutter is closed) but there remains something impressed on the organ of sight, a certain effect on the sense of vision.