The direct correlation between effective radius Re and corresponding surface brightness mu-e, found for early-type galaxies by Kormendy (1977) and later confirmed by several studies, is reexamined using a homogeneous photometric data base relative to a luminosity-limited sample of 33 E and SO Virgo cluster galaxies. Contrary to previous belief, but

Spectroscopic observations of the dwarf nova IR Gem in the range 4000-7000 A, covering a whole orbital period, are presented. The dates of the observations (February 3-6, 1987) were at the end of the decline from an outburst and the beginning of quiescence. Evidence of phase related variations in H-alpha equivalent width is found, showing a maximum

IAUC 5174 available at Central Bureau for Astronomical Telegrams. IAUC 5174 available at Central Bureau for Astronomical Telegrams.

Emission-line and UV continuum observations of the type I Seyfert galaxy NGC 5548 were carried out for a period of 8 months with the IUE satellite. It was found that both the continuum shape and the line ratios of NGC 5548, while being not unusual for type I Seyfert galaxies, are strongly variable. The UV continuum flux and broad emission line

A circular analyzer has been used at the focal plane of a telescope in days of absence of instrumental polarization to simultaneously record I±V spectrograms at two different wavelength ranges: ≡6300 Å and ≡3930 - 3970 Å. The observations have been analyzed within two, also different, frames: on the one hand, an empirical relationship between

The chromatic behaviour of the IAC analyzer, commonly used at the German Vacuum Gregory-Coude telesope at the Spanish Observatorio del Teide (Canary Islands), is investigated. It is shown that, through careful alignment of the optical components, a nearly perfect circular analysis can be obtained at wavelengths of 4000 Å and 6000 Å. For other