The Fiber Multi-Object Spectrograph for the Okayama 188cm Telescope - Development and Observation -

A fiber multi-object spectrograph for the Okayama 188cm telescope (OFMS) has been developed. We found two problems at the observation in 1993. The first was that the spectra were low quality without sufficient photon counts due to smaller efficiency than expected. The second was the complicated procedure in operating the OFMS. We have solved these problems with the development started in 1993. Currently, the OFMS is capable of observing 30 celestial objects simultaneously in a field of view of 1 degree. The resolution of the spectrograph is . It is possible to observe spectra of S/N=100 for a mv=10 star at a 1.25 minutes exposure. In April and May 1999, we observed four open clusters and determined the metallicity [Fe/H] for each. We recorded four metallicities as; +0.15 dex for NGC6709, +0.09 dex for IC4665, ‐0.36 dex for NGC6866, and +0.07dex for NGC6633.