Today between 14:30 UTC and 16:00 UTC I have reduced the gain of the SDB1 angular set point drift control loop by a factor 4.The motivation is that the angular motion of SDB1, especially in TY, looks correlated with the BNS range and with the optical gain fluctuation measured by Hrec.

Figure 1 shows the result compared with beferoe and after. The fluctuations on SDB1 LC TX/TY decrease when the drift control has lower gain, but there is no change in the BNS fluctuation, DARM gain fluctuations, or anything else.