Fibre bundle

Given the low efficiency of the high-resolution fibre and the fact that due to a manufacturing error the medium-resolution simultaneous-ThAr mode could not be used it was decided to prepare and install a new fibre bundle. This was done in June 2007 together with people from Aarhus University in Denmark and Gerardo Avila from ESO. Unfortunately, only 3 out of the 4 fibres worked properly but the 3 show optimal throughput. As the 4$^{th}$ fibre does not work, the planned 'simultaneous sky spectrum mode' cannot be offered. The new bundle does offer, besides the high-resolution simultaneous-ThAr mode, now also medium-resolution simultaneous-ThAr mode. The efficiencies of the new bundle were entered in the Exposure Time Calculator. One thing that still needs to be decided is whether to upgrade the old fibre bundle to serve as a proper spare.