One way to answer the question in the title is to look at the correlation between power fluctuations (for example H1:LSC-POPAIR_B_RF18_I_NORM_MON) and the residual excursion of all ASC error signals from the average value (zero if the loops are closed, non-zero otherwise). This figure of merit can be represented either with a scatter plot, or with a two-dimensional histogram. The plots below show an example for a DRMI lock from yesterday (GPS from 1217614260 to 1217614500). Only input beam and PRC loops were closed. Clearly, the alignment position was not optimal, since all histograms are skewed. If the alignment was tuned at the correct working point, one would expect all histogram to be symmetric, showing round shapes, or at most parabolic, second order, dependencies of the power on the ASC signals (this meaning that the power fluctuations are due to too loose angular controls).

Both plots show the dependency of POP_RF18 on all ASC error signals.