The Mark III very-long-baseline interferometry (VLBI) system allows recording and later processing of up to 112 megabits per second from each radio telescope of an interferometer array. For astrometric and geodetic measurements, signals from two radio-frequency bands (2.2 to 2.3 and 8.2 to 8.6 gigahertz) are sampled and recorded simultaneously at all antenna sites. From these dual-band recordings the relative group delays of signals arriving at each pair of sites can be corrected for the contributions due to the ionosphere. For many radio sources for which the signals are sufficiently intense, these group delays can be determined with uncertainties under 50 picoseconds. Relative positions of widely separated antennas and celestial coordinates of radio sources have been determined from such measurements with 1 standard deviation uncertainties of about 5 centimeters and 3 milliseconds of arc, respectively. Sample results are given for the lengths of baselines between three antennas in the United States and three in Europe as well as for the arc lengths between the positions of six extragalactic radio sources. There is no significant evidence of change in any of these quantities. For mapping the brightness distribution of such compact radio sources, signals of a given polarization, or of pairs of orthogonal polarizations, can be recorded in up to 28 contiguous bands each nearly 2 megahertz wide. The ability to record large bandwidths and to link together many large radio telescopes allows detection and study of compact sources with flux densities under 1 millijansky.

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Resonance Raman and electronic absorption spectra have been measured for the ozonide ion, O−3, produced in single crystals of KClO3 and NaClO3 by irradiation with γ rays. The O−3 ions are oriented in four to six symmetrically nonequivalent positions in KClO3 and appear to be oriented in two nonequivalent positions in NaClO3. Differences between the nonequivalent orientations affect both the ground and excited electronic states of O−3 as well as its ground vibrational states. The progressions of ν1 observed in the electronic spectra show that the vibrational spacing of ν1 in the excited electronic state is about 857 cm−1 as compared with the ground state spacing of about 1020 cm−1. Measurements of relative Raman intensities obtained with different exciting lines indicates that excitation near the center of a vibronic transition (0–n′) produces extra enhancement of the intensity of the nν1 vibrational transition.

We analyzed 37 very long baseline radio interferometry experiments performed between 1972 and 1978 and derived estimates of baseline vectors between six sites, five in the continental United States and one in Europe. We found no evidence of significant changes in baseline length. For example, with a statistical level of confidence of approximately 85%, upper bounds on such changes within the United States ranged from a low of 10 mm/yr for the 850 km baseline between Westford, Massachusetts, and Green Bank, West Virginia, to a high of 90 mm/yr for the nearly 4000 km baseline between Westford and Goldstone, California. We also obtained estimates for universal time and for the x component of the position of the earth's pole. For the last 15 experiments, the only ones employing wideband receivers, the root‐mean‐square differences between our values and the corresponding ones published by the Bureau International de l'Heure are 0.0012 s and 0.018 arc sec respectively. The average value we obtained for the radial Love number h for the solid earth is 0.62±0.02 (estimated standard error).

The 21-cm absorption spectrum of BL Lacertae indicates that it is more than 200 pc, and possibly less than 2 kpc (z = -350 pc) distant. Arguments are presented for the position that the data are consistent with BL Lac's being extragalactic.