An experimental Adaptive Optics system utilizing a low-altitude Rayleigh Laser Guide Star is presented. The current status of the project is described together with plans for future work, with the ultimate goal of providing demonstration Rayleigh LGS AO science on the 4.2m William Herschel Telescope. The implementation of the demonstration system

The spectra of two early B-type supergiant stars in the Sculptor spiral galaxy NGC 300 are analyzed by means of non-LTE line-blanketed unified model atmospheres, aimed at determining their chemical composition and the fundamental stellar and wind parameters. For the first time, a detailed chemical abundance pattern (He, C, N, O, Mg, and Si) is

This presentation reports the numerical simulations we have done in order to evaluate the performance of the first-light AO system of LBT. The simulation tool used for this purpose is the Software Package CAOS, applicable for a wide range of AO systems and for which a brief recall of the main features is made. The whole process of atmospheric

We describe a coronagraph facility built for use with the 4.2 metre William Herschel Telescope (WHT) and its adaptive optics system (NAOMI). The use of the NAOMI adaptive optics system gives an improved image resolution of ~0.15 arcsec at a wavelength of 2.2 microns. This enables our Optimised Stellar Coronagraph for Adaptive optics (OSCA) to null

Measurements of the 7Li/6Li ratio in the local interstellar medium (ISM) towards o Per and ζ Per by Knauth et al. (2000, AAA 073.131.129) show clouds with a range from near 2 (a value which points to GCR production by spallation or alpha + alpha to near 11 (the solar system value). These values can be very well accounted for within our model of

The sources discovered in deep hard X-ray surveys with 2-8 keV fluxes of S2-8˜ 10-14 erg cm-2 s-1 make up the bulk of the X-ray background at these energies. Here we present detailed multiwavelength observations of three such sources from the European Large-Area ISO Survey Deep X-ray Survey. The observations include sensitive near-infrared