STATUS AND SCIENTIFIC PERFORMANCE OF ELMER, A MULTI-PURPOSE INSTRUMENT FOR THE GTC

ELMER is an instrument for the GTC designed to observe between 365 and 1000 nm. The observing modes for the instrument at Day One shall be: Imaging, Long Slit and Mask-Multi-object Spectroscopy, Slit-less multiobject spectroscopy, Fast Photometry and Fast short-slit spectroscopy, over a FOV of 4.2 arcmin diameter. Spectral resolutions of 250, 1000 and 2500, covering the whole spectral range, will be available. ELMER has been designed and managed within the GTC Project Oce. ELMER is currently in the nal stage of testing previous to be shipped to the Observatory. The general description of this instrument and its expected scientic performance are summarised.