An analysis of the 5 minute oscillation in the solar photosphere has been carried out using an inversion of the radiative transfer equation applied to a time-series of K I lambda 7699 line spectra with a 5" x 5" window at disk center. A thorough discussion of the inversion conditions, with special emphasis on the LTE approach and a careful error

We present simultaneous two-dimensional spectroscopy of the circumnuclear region (12" x 9") of the galaxy NGC 7331, obtained with an optical fiber system coupled to the ISIS double spectrograph of the 4.2 m William Herschel Telescope. The system allows simultaneous observation of 125 regions of this galaxy in two spectral ranges: 4590--5400

GOLF in-flight commissioning and calibration was carried out during the first four months, most of which represented the cruise phase of SOHO towards its final L1 orbit. The initial performance of GOLF is shown to be within the design specification, for the entire instrument as well as for the separate sub-systems. Malfunctioning of the polarising

We present the optical and UV emission-line properties of 160 X-ray-selected active galactic nuclei (AGN) taken from the RIXOS survey (including Hα, Hβ, [Oiii] lambda5007, Mgii lambda2798 and Ciii] lambda1909). This sample is believed to contain a mixture of absorbed and unabsorbed objects, with column densities up to ~4x10^21cm^-2. Although the

Nine months' seeing statistics at the Observatorio del Roque de los Muchachos (ORM) are presented. Measurements were taken with a differential image motion monitor on top of a 5-m high tower. From the whole campaign the mean seeing is 0.76", the median value is 0.64" and 7% of the time the seeing is better than 0.3". The best seeing measured is 0

The in-flight performance of the total and spectral irradiance instruments within VIRGO (Variability of solar IRradiance and Gravity Oscillations) on the ESA/NASA Mission SOHO (SOlar and Heliospheric Observatory) is in most aspects better than expected. The behaviour during the first year of operation of the two types of radiometers and the