The power spectrum of more than 630 days of full-disk solar velocity data, provided by the GOLF spectrophotometer aboard the Solar and Heliospheric Observatory, has revealed the presence of modelike structure well beyond the acoustic cutoff frequency for the solar atmosphere ( nu _{{ac}}~5.4 mHz). Similar data produced by full-disk instruments

The splitting of the frequencies of the global resonant acoustic modes of the Sun by large-scale flows and rotation permits study of the variation of angular velocity Omega with both radius and latitude within the turbulent convection zone and the deeper radiative interior. The nearly uninterrupted Doppler imaging observations, provided by the

Spatially resolved long-slit spectrophotometric data for the planetary nebulae PB 6, NGC 2452, NGC 2867, NGC 6905 and He 2-55 are presented. Different knots were observed in each nebula. All the nebulae are ionized by [WC 2-3] type nuclei. For the five objects, we calculated photoionization models using the ionizing radiation field from models of

It is foreseen that the Gran Telescopio Canarias will include an Adaptive Optics (AO) system to provide diffraction-limited images in the near-IR. The preliminary scientific requirements are presented here and are used to determine the basic system specifications. The sky coverage is determined for the cases of natural and laser guide stars. The

We present a new technique for performing two-dimensional (integral-field) spectroscopy of objects with a large range in intensity. It is based on the capability of optical fibers to discretize the intensity distribution at the telescope focal plane. This allows not only reformatting but also the equalization of fiber output intensities, matching

We present accurate measurements of the central wavelengths of 4947 atomic absorption lines in the solar optical spectrum. The wavelengths, precise to a level ~ 50-150 m s(-1) , are given for both flux and disc-centre spectra, as measured in relatively recent FTS solar atlases. This catalogue modernizes existing sources based on photographic