The Very Large Array (VLA) is presently being constructed on the Plains of San Augustine near Socorro, New Mexico by the National Radio Astronomy Observatory. The purpose for which this instrument is being constructed is to produce “radio images” of resolution comparable to that of large optical telescopes. There have already been several “test” observations, some successful, using the partially completed instrument to study the molecular species of OH, H2O, and NH3 with wide bandwidths (200-1500 kHz).

During the past week we have heard a considerable number of papers dealing with spectroscopic observations in the 1-5μm region of the infrared. I predict that as instruments and detectors continue to improve, such observations will play a major role in the study of interstellar molecules in both molecular clouds and circumstellar clouds around evolved stars. Fourier Transform spectrometers and Fabry Perot interferometers have already yielded spectra of such sources with spectral resolution and radial velocity precision fully comparable to millimeter wave observations. The critical need is to improve the limiting magnitude of such observations by 3-5 stellar magnitudes so that one can study large numbers of sources rather than the few brightest in each class.

Infrared heterodyne spectroscopy is extremely useful in determining by precise measurements of atomic and molecular infrared line spectra the molecular abundances, velocity structure, and excitation conditions of the interstellar medium, and the temperature- and pressure-profiles of planetary atmospheres (cf. Kostiuk et al. 1977, Betz et al. 1976, 1977, Abbas et al. 1978).

The observation of molecular phenomena in interstellar clouds by spectroscopy in the longer wavelength region of the infrared is discussed. This is a region where sensitivity is almost universally affected by background continua, appropriate techniques may be either coherent or incoherent, and work above most of the atmosphere is required for much of the spectral range. So far, only a very limited amount of molecular work has been done in the far-infrared, but one can expect fairly rapid growth and important results.

Previous suspicions of large quantities of BS in large astronomical associations have been confirmed by observation.