Author Description

Excerpt from A Comparison of Stellar Radiometers and Radiometric Measurements on 110 Stars An extensive series of measurements of the radiation from Arc turus, Vega, Jupiter, and Saturn were made by Nichols5 by means of his radiometer which, like the thermopile, absorbs all the radia tions of all wave lengths falling upon it. The receivers were 2 mm in diameter. A candle at a distance of 1 m would have given a deection of 724 mm. He used a 2-foot reector and observed deections of 1 to 2 mm. In fact, deections which were larger than 2 mm were considered false, while frequently they were of wrong sign. The sensitivity of his radiometer was such that a deection of 1 mm would be caused by 750 000 of the heat received on a surface equal to the aperture of the concave mirror from a candle at 1 meter distance. Or, neglecting atmospheric absorption, the sensitivity was such that by using the 2-foot mirror to focus an image of the ame upon the radiometer he would have obtained a deection of 1 mm from the candle placed at a distance of 5 miles. He concluded that the thermal intensity was Vega: Arcturus: Jupiter: Saturn= 1 As for the possibil ity of further work he concluded that by using a 5-foot reector it would be possible to observe white stars down to the second magnitude and red stars possibly to the third magnitude. The Boys 6 radiomicrometer has also been tried in measuring radiation from stars. The instrument was used with a 16 - inch reecting telescope. The slight deections obtained on various planets and stars were regarded as of questionable origin. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This 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 origin