HARPS Gets New Fibres After 12 Years of Operations

It was already known that circular fibres carry some memory effect of the angular and spatial distribution of the injected light. However, only later it was understood that far-field changes dramatically impact the IP of the spectrograph in presence of optical aberrations ( Perruchot et al., 2010). In the meantime, non-circular fibres had become available and it was demonstrated, by simulation and laboratory tests, that their scrambling efficiency is far superior to that of circular fibres (see Figure 1 and Chazelas et al. [2010], Figures 5 and 10).