Science Progress in the Twentieth Century, Vol. 5

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Excerpt from Science Progress in the Twentieth Century, Vol. 5: A Quarterly Journal of Scientific Work and Thought, July 1910 to April 1911The simpler name "star map" is here applied to the chart generally known as the " Astrographic Chart, " because this latter conveys a suggestion of technicality which is absent from the project. What astronomers in different parts of the world are really about is the making of a large and much more detailed map of the stars than has hitherto been produced. The map is being made by photography, but though the word "astrographic" has been coined for use when photography is applied to the stars, the work does not involve much technicality that is not familiar to the users of an ordinary Kodak. In three details only does the work of the astronomer differ from that of the amateur photographer: he uses a much longer camera, he drives the camera by clockwork so that it may follow the stars, and he takes pictures at night instead of in the daytime. It may perhaps be added that he uses the light emitted by the stars, instead of photographing objects by the reflected light of the sun. But of these details more presently.Let us first consider what is the nature of a map of the stars, as this differs somewhat in character from the maps of the earth's surface with which we are familiar. There is no question of finding our way, no question of delimiting property, no question of showing hills and valleys. A map of the stars is of a more monotonous character, being practically limited to showing the exact positions and the brightnesses of individual points of light.About the PublisherForgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.comThis book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully, any imperfections that remain are intentionally left to preserve the state of such historical works.