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The VIRMOS consortium of French and Italian Institutes is manufacturing 2 wide field imaging multi-object spectrographs for the European Southern Observatory Very Large Telescope, with emphasis on the ability to cany over spectroscopic surveys of large numbers of sources. The VIsible Multi-Object Spectrograph, VIMOS, is covering the 0.37 to 1 micron wavelength domain, with a full field of view of 4x7x8 arcmin2 in imaging and MOS mode. The Near InfraRed MultiObject Spectrograph, NTRMOS, is covering the 0.9 to 1 .8 microns wavelength range, with a field of view 4x6x8 arcmin2 in MOS mode. The spectral resolution for both instruments can reach up to R5000 for a 0.5arcsec wide slit. Multi-slit masks are produced by a dedicated Mask Manufacturing Machine cutting through thin Invar sheets and capable of producing 4 slit masks -300x300mm each with 2OO slits 5.7mm long (10 arcsec) in less than one hour. Integral field spectroscopy is made possible in VIMOS by switching in the beam specially build masks fed by 6400 fibers coming from a 54x54arcsec2 integral field head with a 80x80 array of silica micro-lenses. NIRMOS has a similar IFS unit with a field of 30x30 arcmin2. These instruments are designed to offer very large multiplexing capabilities. In MOS mode, about 1000 objects can be observed simultaneously with VIMOS, with a SIN1O obtained on galaxies with 124 in one hour, and 2OO objects can be observed simultaneously with NIRMOS, with a S/N10 obtained on galaxies with J22, H20.6 in lh at R2OO (R,bS25OO). We present here the status of VIMOS, currently under fmal integration, with expected first light in the summer 2000, together with the fmal design of NTRMOS presented at the Final Design Review. The VLT-VIRMOS deep redshift survey of more than 1 50000 galaxies over the redshift range O

A well-adapted spectrograph concept has been developed for the SNAP (SuperNova/Acceleration Probe) experiment. The goal is to ensure proper identification of Type Ia supernovae and to standardize the magnitude of each candidate by determining explosion parameters. An instrument based on an integral field method with the powerful concept of imager slicing has been designed and is presented in this paper. The spectrograph concept is optimized to have very high efficiency and low spectral resolution (R~100), constant through the wavelength range (0.35-1.7µm), adapted to the scientific goals of the mission.

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