We present observations of a Mg X 625 Å coronal line, obtained with the CDS instrument on SoHO, extending from the disk part of the coronal hole to ~ 90 000 km above the limb in the north polar coronal hole. Observations were performed in polar plumes and inter-plume lanes. To obtain a sufficiently high signal-to-noise ratio the observations were

Tight stability requirements for the imager/spectrograph OSIRIS (a Day One optical instrument for the GTC telescope) demand a careful treatment of thermal effects within the OSIRIS camera. Mostly due to the thermal response of refraction indices of its glasses (and not so much to curvature, spacing or thickness variations of the lenses), the camera

We present optical photometry of XTE J2123-058 taken in 1999 and 2000, during its quiescent state. The dominant feature of our R-band light curve is the ellipsoidal modulation of the secondary star; however, in order to fit this satisfactorily, we require additional components that comprise an X-ray-heated Roche lobe-filling secondary star and an

We present here the results of an imaging study of eight grand-design and two intermediate-arm galaxies, based on CCD observations in U, B, V, R and I. We give grey-scale images, both in individual and in colour indices. Also we present a decomposition into bulge and disc following an iterative method. This provides us with a reasonable estimate of

Photospheric abundances are presented for 27 elements from carbon to europium in 181 F and G dwarfs from a differential local thermodynamic equilibrium (LTE) analysis of high-resolution and high signal-to-noise ratio spectra. Stellar effective temperatures (Teff) were adopted from an infrared flux method calibration of Strömgren photometry. Stellar

We describe an unusual undergraduate course that has been running successfully for over ten years and is built around a two-week field trip to Tenerife. The purpose of the visit is twofold: firstly to spend a week working in collaboration with students from the Universidad de La Laguna and secondly to spend a week at the Observatario del Teide