  VIMOS (VIsible Multi-Object Spectrograph) is a multi-object imaging
spectrograph installed at the VLT (Very large Telescope) at the ESO (European
Southern Observatory) Paranal Observatory, especially suited for survey work.
VIMOS is characterized by its very high multiplexing factor: it is possible to
take up to 800 spectra with 10 arcsec long slits in a single exposure. To fully
exploit its multiplexing potential, we designed and implemented a dedicated
software tool: the VIMOS Mask Preparation Software (VMMPS), which allows the
astronomer to select the objects to be spectroscopically observed, and provides
for automatic slit positioning and slit number maximization within the
instrumental constraints. The output of VMMPS is used to manufacture the slit
masks to be mounted in the instrument for spectroscopic observations.
