The Free-Oscillation band during the last 30 days

Click on respective image to view it in original size.
Want to see older spectrograms? Explore subdirectories for the years | 2018 | 2017 | 2016  | 2015 starting in June |
Path model:  http://holt.oso.chalmers.se/hgs/SCG/PNG/<year>/<month>/<day>-last-30-days.f<C>.png   e.g.  http://holt.oso.chalmers.se/hgs/SCG/PNG/2015/06/01-last-30-days.fo.png
where <C> is a mark for the frequency range; in earlier years  o  or w , in later years  m
  0 - 20 mHz
0 - 5 mHz

The white curve shows air pressure
frequency of the almost ever persistent oscillation near 2 mHz
The OSG 054 seems to be a rare case where

(not drawn to any scale). You might notice covariation with the
which we believe originates in the Heater Current control loop.
this current has a noticeable effect on the gravity sensor.