(unknown author using Matt's alog account)

This is a (sort of) follow-up of https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=3508.

In the attached, you'll see the calibrated spectrum of this morning (red), last evening at about 9PM (blue), last evening at about 4PM (green, the same one as what Matt posted), and some old reference (brown).

There are several things to note:

1. New 0.7Hz-ish sharp line

In the newer two traces, there's a 0.695Hz line which is new to me.

There should be no difference between green and blue except environment noise as far as I can tell.

2. Low frequency

Red, blue and green are all worse than brown at f<0.1Hz. Somebody needs to do on/off test to identify what's offending.

3. High frequency

High frequency noise at f>5Hz apparently changes with time.

4. Vincent's thing is definitely good for 0.2Hz