At yesterday morning's meeting it was pointed out that there are temperature fluctuations in the laser room. Sure enough plots of the temperature at the north and south ends of the table, and the relative humidity, do show repetitive excursions. One thing that is a little puzzling is that the same temperature excursions are not seen by an AD590KF temperature sensor that is located on the table after the reference cavity. There is no low pass filtering that I am aware of that would mask the trend. The other option is that the temperature sensor interface box is not working. However the last time it was examined in the EE Lab (~1 - 2 years ago) is was just fine. The LED power indicators on the front panel do not suggest anything untoward. So I cannot explain the different signals.