ASTROPHOTOGRAPHY

The application of photography to astronomy may be considered one of the greatest advances made in the science. The recording, by hand, on paper, of astronomical observations, leaves room for serious personal error, whereas a photograph nece arily gives a picture which is both faithful and complete. In obtaining precise measurements of celestial bodies and their movements, photography is found to be of increasing value, while a further use of the camera is made in producing photographs of stellar spectra. The first succe ful astronomical f photograph is credited to an American photographs of the moon in the year 1840. Since that time there have been many notable accomplishments in this branch of the science. The planet Eros was discovered by photography, and this body is now known to be, with the exception of the moon, our nearest neighbor in space. Many comets have also been discovered and exact measurements of the distance between the earth and remote bodies have been made. In the later years of last century, the English astronomer, Gill, conceived the idea of preparing a complete catalogue of the heavens, and in 1887 a meeting was called at Paris, by the French Government, at which delegates attended from all civilized countries. At this were made for putting Gill’s suggestion into effect. Eighteen observatories were engaged in the colo al undertaking, which involves the exposure of over 44,000 plates. It is estimated that 20,000,000 stars will be photographed, 2,000,000 of which will be measured and recorded in the catalogue. Over thirty years be required for the work which is now almost complete.