The effects of seeing on Sérsic r1/n profile parameters are extensively studied using a Moffat function. This analytical approximation to the point spread function (PSF) is shown to provide the best fit to the PSF predicted from atmospheric turbulence theory when β~4.765. The Moffat PSF is additionally shown to contain the Gaussian PSF as a

We present R-band observations of the Cosmic Lens All-Sky Survey gravitational lens system B1152+199, obtained with the active optics system at the Telescopio Nazionale Galileo. Owing to the very good spatial resolution of the images (0.6"), the optical counterpart of the two quasar components and the lens galaxy have been clearly identified

An exceptional variability phase occurred in the peculiar F-type hypergiant ρ Cas (Ia+) when the V brightness dimmed by about a full magnitude between June and September 2000. The star recovered from this deep minimum by April 2001. It is the third outburst of ρ Cas on record in the last century. We detect the formation of TiO bands in high

We obtained at the same time G-band images at the Dutch Open Telescope (DOT) on La Palma and spectropolarimetric data in the near infrared at the German Vacuum Tower Telescope (VTT) on Tenerife. The spectropolarimetric data show interesting correlations. Bright filaments have a smaller magnetic field s trength, and higher Evershed velocities occur

We present a method to reduce noise in helioseismic power spectra using a non-orthogonal wavelet transform based on quadratic spline functions. The quality of our method is tested by applying it to artificially generated time-series approximating solar p-modes. The mode frequencies and line widths obtained from least-squares fits to the smoothed

We have obtained intermediate resolution optical spectra of the black-hole candidate Nova Sco 1994 in June 1996, when the source was in an X-ray/optical active state (R~15.05). We measure the radial velocity curve of the secondary star and obtain a semi-amplitude of 279+/-10 km s-1 a value which is 30 per cent larger than the value obtained when