Under a contract with the GRANTECAN, the Commissioning Instrument (CI) is a project developed by a team of Mexican scientists and engineers from the Instrumentation Department of the Astronomy Institute at the UNAM and the CIDESI Engineering Center. The CI will verify the Gran Telescopio Canarias (GTC) performance during the commissioning phase

We briefly recall the principle of the polychromatic laser guide star, which aims at providing measurements of the tilt of incoming wavefronts with a 100% sky coverage, We describe the main results of the feasibility study of this concept undertaken within the ELP-OA porgramme. We finally summarize our plans for a full demonstrator at Observatoire

A rationale is presented for the use of a relatively low-altitude (15km) Rayleigh Laser Guide Star to provide partial adaptive optics correction across a large fraction of the sky on the 4.2m William Herschel Telescope. The scientific motivation in relation to the available instrumentation suite is discussed and supported by model performance

Having acquired since July, 1989, a complete 11-year solar cycle of full disk data, the IRIS++ network has now made available to anyone the longest helioseismic data base to-date. A few results obtained from this very long time series are briefly presented here, with some emphasis on the low degree p-mode frequencies themselves, and their

We present outburst spectroscopy of GX 339-4 that may reveal the motion of its elusive companion star. N III lines exhibit sharp emission components moving over ~300 km s-1 in a single night. The most plausible interpretation of these components is that they are formed by irradiation of the companion star and the velocities indicate its orbital

Chemical abundance data for the Galaxy show a wide dispersion. We try to check if this dispersion may also be found with chemical evolution models as an effect of variations of an Initial Mass Function (IMF) which follows a Poisson's distribution