Through a high-resolution spectroscopic survey, we analyze the velocity field of 16 planetary nebulae with [WC]- or wels-type nuclei in comparison with 8 nebulae having other central star types. We found spectral evidence for finite turbulent velocities in [WC]-type planetary nebulae superimposed on an essentially constant expansion velocity

We present a cross-correlation between the European Large Area ISO Survey (ELAIS) 15-μm ISO survey with the ROSAT (0.1-2keV) all-sky survey and the pointed observations WGACAT source catalogue. The resulting sample contains 15 objects. Optical spectroscopic identifications exist for 13 objects: six broad-line quasi-stellar objects (QSOs), four

At the First International Conference on Comet Hale-Bopp (Canaries, 1998) many astronomers agreed with the value of the period of axial rotation of its nucleus, which was obtained by observers by a comparison of the two sequential patterns of the dust arcs. It was noted that the pattern had been repeated each ~12 hours. The value 11.35 h was taken

Within the framework of the European Space Agency (ESA) SILEX project, aimed at experimentally demonstrating the feasibility of inter-satellite optical communications links, an Optical Ground Station (OGS) has been built by ESA in the premises of the Instituto de Astrofisica de Canarias (IAC, Institute of Astrophysics of the Canary Islands)

Amateur astronomers have always represented an important observing group in cometary astronomy. Much of our knowledge of cometary light curves has come from amateur data, initially in the form of total visual magnitude estimates and now increasingly in the form of CCD observations. The increasingly widespread use by amateur astronomers of CCD

We present near-infrared 1.5-2.5μm moderate-resolution long-slit spectra of two Seyfert 1 galaxies (NGC 1097 and 1566), three Seyfert 2s (NGC 1386, 4945 and 5128) and one Seyfert 1.5 (NGC 3227), both parallel to an ionization cone or jet and perpendicular to it. The spectra are used to study the spatial extent of the line emission, integrated