A discussion on infared astronomy - Millimetre and submillimetre astronomy

Abstract

Measurements of lunar radiation at a wavelength of 1.2 mm are described and discussed. It is found that the lunar poleward darkening function T(Xf)/T(0X) varies considerably more rapidly with latitude V than is predicted by a plane homogeneous model. Preliminary calculations using a centimetre scale roughness model are described. The results account well for the measured values of the darkening function at 1.2 mm as well as for measurements of the corresponding function at both longer and shorter wavelengths. Close to lunar dawn upland lunar areas appear to have higher brightness temperatures than the maria. Some measurements of the partial solar eclipse of 20 May 1966 are reported together wit observations of radiation from the planet Jupiter. The relative advantages of Fourier transform and filter spectroscopy at millimetre and submillimetre wavelengths are discussed. A possible experiment to detect the cosmic thermal 3 °K background at 1.3 and 1.9 mm length is discussed.