K. Venkateswara

I was looking at the BRS DriftMon signal to see how stable the BRS centering was, after being reset yesterday. I noticed very clear ~3.5 hour period oscillations. I know the beam-balance has a low resonance frequency but not that low! So I checked the temperature and sure enough it seems to be oscillating with 0.1 deg C amplitude. Note that it almost looks like the BRS is leading the oscillation, which is of course not possible. It turns out the temperature coupling has a negative sign ( as can be seen in 15174) and a lag of hours leading to a phase lag of ~160 deg, not a phase lead of ~20 degrees :)

This is probably not a big deal but I thought it looked cool.