Naoki, Sheila, Camilla

In alog74059, it was pointed that the 80Hz BLRMS increased by 1.5dB after FC2 centering on October 27th, and this could be due to FC detuning change caused by the FC2 centering. Today we changed the FC detuning by +- 20 Hz from the nominal -28 Hz, but the nominal detuning seems already optimal as shown in the attached figure. We left the FC detuning at nominal value -28 Hz.