Fig. 13.

OPD residuals as a function of coherence time (at 500 nm) for all calibrators and GC data taken between July 2017 and November 2018 in the 909 Hz mode. The dashed vertical lines correspond to the first quintile (3 ms) and last quintile (7 ms) of the coherence time distribution as observed by the ESO astronomical site monitor (ASM) at visible wavelength. The thick lines correspond to the first and last quintile of the OPD residual distribution (purple for UTs and red for ATs). The median fringe-tracking residuals are 150 nm on the ATs and 250 nm on the UTs.
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