We report four colour CCD photometry and photoelectric photometry of 3C 345 taken in the spring of 1990. After an initial partial recovery from the minimum observed in 1989 which was, at that time, the deepest ever recorded, a very fast decline to even fainter levels was seen over ten days in May 1990, which was then followed by a further partial

The mechanism proposed by Kormendy (1984) for the formation of counterrotating cores in elliptical galaxies is investigated using self-consistent numerical simulations of mergers between a high- and a low-luminosity elliptical galaxies. The conditions for a counterrotation to appear are determined, observational properties of the remnants are

IAUC 5129 available at Central Bureau for Astronomical Telegrams. IAUC 5129 available at Central Bureau for Astronomical Telegrams.

IAUC 5123 available at Central Bureau for Astronomical Telegrams.

IAUC 5115 available at Central Bureau for Astronomical Telegrams.

We develop a method for computing the probability densities of spherical voids in distribution of galaxies on a large scale. This method is applied to Poissonian cluster models. We consider CDM biased and non-biased models; the appropriate approximation has been used in each case. We find that, in the latter case, the probability finding a void