The beam alignment into the reference cavity was tweaked. Most of the alignment was done by adjusting the mirror mounts on the periscope. The other mounts did not yield as much gain as the ones on the periscope. With the pitch adjustments the transmission signal went from ~0.75 - 0.78 to ~1.16. Relatively minor tweaks were made to the AOM alignment without any big improvements, which suggests that the adjustments for the AOM are in the mid-range. Went back to the periscope adjustments and adjusted yaw which improved things to ~1.2. Walking the beam in yaw, followed by small pitch adjustments improved the signal to ~1.5 with the HEPA fans on and the ISS unlocked. The power into the reference cavity was measured to be 30.1 mW - measured with Ophir stick calorimeter. Both mounts on the periscope were locked as best as possible. The transmission signal was 1.52. The signal on the RFPD was: unlocked : -245 mV locked : -40 mV offset : -2 mV With the ISS on, the reference cavity transmission was measured to be 1.54. Attached, for reference, is the camera image of the various spots from the cavities. As an aside, the recent drift in reference cavity transmission seems to coincide with some jumps in the pre-modecleaner temperature. Jason, Ed, Peter