Radio-astronomy, Radiometry and Infra-red Techniques

The year 1932 was one which had no great apparent significance for navigators, and yet it saw the commencement of two new lines of research which today, after an interval of more than a quarter-of-a-century, promise important contributions to the safety of navigators both at sea and in the air.The two lines of research were superficially quite unrelated, but fundamentally they relied upon the same principle—the detection of radiant energy emitted by objects solely as a result of their temperature. The first of these small beginnings was the discovery by K. G. Jansky that radio waves could be detected from extra-terrestrial sources: the second was the commencement by the U.S. Signal Corps Engineering Laboratories of an intensive study of infra-red devices with the object of obtaining night vision without illumination of the field of view.From Jansky's discovery has sprung the whole science of radio astronomy, which has revolutionized our ideas about the universe, and brought in its wake, as one practical benefit, the radio sextant. From the work of the U.S. Signal Corps there resulted a number of very useful infra-red components, including the pneumatic detector, better known as the Golay cell.