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Emission features of C2 C3, CN, and dust in Comets Thiele (1985m), Hartley-Good (19851), and Giacobini-Zinner (1984e) have been analyzed and their mass loss rates of about 0.5, 1.1, and 0.8 Mg S-1 have been determined.

Since the discovery of the 616-523 rotational transition of interstellar water in maser emission, several hundred sources have been discovered. Their profiles are very variable, presenting correlated variability (Gammon, 1976) or anticorrelated variability (Cesaroni, 1990). Several models have been proposed to explain this variabi1ity. Strong Galactic masers, such as W49 and W51 (Kylafis et al. 1991), and also an extremely strong outburst detected by Abraham et al. (1981) in Orion, could not be fully explained based on current models. We have monitored from October 1989 to July 1991 a very strong water vapour eruption in the +28 km s-1 feature, originated from W49N. Here we present the results and discuss the possible correlated variability of this feature with the one that appeared at +62 km s-1.

The H2O maser source in G305.8 - 0.2 was first detected by Haynes et al. (1984). Inspection of the Southern Hemisphere radio surveys did not show any strong compact HII region or water maser placed nearby this source. The IRAS point source catalog (2.0) shows a strong source in the direction of the maser. We analysed the temporal variation and line profile of the H2O maser emission and discussed the nature of its associated IRAS source. These source characteristics seem compatible with the hypothesis that the maser is associated with a protostellar disk around an early-type star of spectral type 07 to 09 surrounded by a spherical shell of gas and dust.

The first spectra of southern H2O masers obtained with the 14-m Itapetinga radio telescope are described. A new H2O source was found in H2-3 (G345.4–0.9).

The emission of circularly polarized radiation of reversed senses from the respective solar hemispheres at λ = 4.3 cm is discussed, referring to consistent eclipse results obtained in November 1966 (Figure 1), March 1970, and January 1973 (Figure 2). Further qualitative information were obtained by performing a series of 18 daily solar maps (Figure 3) at the same wavelength, with moderate angular resolution (i.e., 12′). We were not able to resolve individual centers’ polarities, but have confirmed that reversed senses of circular polarization occur, tending to be right-handed at southern areas of the solar disk, and left-handed at northern areas. These senses correspond to preceding polarities at the hemispheres for the 20th solar cycle, and a ‘neutral line’ divide the two polarized hemispheres, showing a contour that depends strongly on the presence of active centres and on their displacement with solar rotation. This suggest that the polarized features are strongly controlled, if not completely, by the presence of photospheric underlying magnetic areas.