The near-infrared spectrograph LIRIS was first commissioned on the WHT on the nights of 15-19 Feb 2003. During all that time the instrument functioned with no major failures. At the time of commissioning LIRIS included imaging and spectroscopic observing modes. Spectroscopy could be done at low resolution (about 700 using the narrowest slit of 0.65

Studying the earliest stages in the birth of stars is crucial for understanding how they form. Brown dwarfs with masses between that of stars and planets are not massive enough to maintain stable hydrogen-burning fusion reactions during most of their lifetime. Their origins are subject to much debate in recent literature because their masses are

The primary challenge of Global Oscillations at Low Frequency New Generation (GOLF-NG) is the detection of the low-frequency solar gravity and acoustic modes, as well as the possibility to measure the high-frequency chromospheric modes. On June 8th 2008, the first sunlight observations with the multichannel resonant GOLF-NG prototype spectrometer

LIRIS is a near-infrared (1-2.5 microns) intermediate resolution spectrograph (R=1000-3000) with added capabilities for multi-slit, imaging, coronography, and polarimetry, built by the IAC as a common instrument for the 4.2m WHT (La Palma, Spain). LIRIS has been used as a visiting astronomer instrument at the WHT since summer 2004. The image

Large telescopes require a very precise calibration in order to maximize its scientific output. Current catalogues of standard stars are generally too bright for 10m telescopes. For GTC we are planning to produce a catalogue with calibration stars which are suitable for this telescope. In this paper we describe the first steps of the GTC

The radiative transfer equation (RTE) gives us information about how the light streams through the medium. It must be inverted in order to obtain the properties of the medium that generated the observation. While there are a number of well discussed methods to approach the solution of the inversion, none of them is suitable for the real-time