We present two conceptual optical designs for a new refractive corrector for the prime focus of the 4.2m William Herschel Telescope, optimised to allow wide-field multi-object spectroscopy. The proposed designs satisfy the demanding requirement that the PSF be smaller than 0.5 arcsec (80% encircled energy) over a two degree FOV and a wavelength

We investigate the role of stellar mass in shaping the intrinsic thickness of galaxy discs by determining the probability distribution of apparent axial ratios (b/a) for two different samples that probe the faint end of the galaxy luminosity function. We find that the b/a distribution has a characteristic `U-shape' and identify a limiting mass M* ~

The star formation rate (SFR) is a key parameter in the study of galaxy evolution. The accuracy of SFR measurements at z ~ 2 has been questioned following a disagreement between observations and theoretical models. The latter predict SFRs at this redshift that are typically a factor 4 or more lower than the measurements. We present star-formation

Context. The CoRoT mission is in its third year of observation and the data from the second long run in the galactic centre direction are being analysed. The solar-like oscillating stars that have been observed up to now have given some interesting results, specially concerning the amplitudes that are lower than predicted. We present here the

We present new B, V and I CCD time-series photometry for 177 variable stars in a 13 × 13arcmin2 field centred on the globular cluster M54 (lying at the centre of the Sagittarius dwarf spheroidal galaxy), 94 of which are newly identified variables. The total sample is composed of two anomalous Cepheids, 144 RR Lyrae stars (108 RR0 and 36 RR1), three

EST (European Solar Telescope) is a 4-m class solar telescope, which is currently in the conceptual design phase. EST will be located at the Canary Islands and aims at observations with the best possible spectral, spatial and temporal resolution and best polarimetric performance, of the solar photosphere and chromosphere, using a suite of