We analyze the sample of measured nuclear magnitudes of the observed Jupiter family (JF) comets (taken as those with orbital periods P 20 years and Tisserand parameters T > 2). We find a tendency of the measured nuclear magnitudes to be fainter as JF comets are observed with CCD detectors attached to medium- and large-size telescopes (e.g

The two Fanaroff & Riley classes of radio galaxies are defined by radio morphology, and the distinction may arise from a combination of environmental conditions and central engine power. Several studies have suggested that powerful, FR II, radio galaxies are on average 0.5 mag fainter optically (i.e., are smaller) than weak, FR I, radio galaxies

The thermal spectrum of the zodiacal light cannot be observed from the ground. We collected 27 mid-infrared (6-12mu m) spectra obtained by the spectrophotometer ISOPHOT-S on-board the Infrared Space Observatory (ISO). The observed positions are distributed over the sky region accessible by ISO. The spectrum of the zodiacal light is remarkably well

We have studied the kinematics of the HH 399 jet, which was recently discovered in the Trifid Nebula. The data were obtained in the [N II] 6583 Å line with a scanning Fabry-Pérot interferometer (TAURUS-2) and in the [S II] 6717, 6731 Å lines with an echelle spectrograph. The analysis of the radial velocities measured along the jet indicates that

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We present calibrations of the effective temperatures of giant stars versus [Fe/H] and colours (U-V), (B-V), (R-I), (V-R), (V-I), (V-K), (J-H), (J-K), (I-K), (V-L'), (b-y) and (u-b). These calibrations are based on a large sample of field and globular cluster stars which roughly cover spectral types from F0 to K5. Their effective temperatures