With Washimi-san

See pictures in the album BS Remedying work after O3.

We proceeded to add ballas mass.

• See these related reports: klog 15651 and klog 15658.
• See the conditions of the initial positions of the different stages and temperature in this screenshot and in my notes. 
• Initial temperature: 23.1 degrees
• Final temperature: 23.5 degrees.

We did two iterations:

• First, we added 2 X 35 gr, in the -Y and +Y sides of BF top, and the F1 keystone went down to around 203 µm from 521 µm.
• Later we removed two grams each side, this is, we added 2 X 33 gr in total, however, the keystone remained at around 203 µm due to the large temperature increase.

Observations

• The temperature increase didn't allow us to realistically assess the effect of adding mass, but the F1 keystone is already reltively close to 212 µm, namely, it's about 16 µm below the goal at 23.4 degrees.
• The screw fastening the masses in the +Y side was tightened by hand and for the one in the -Y side I gently used an Allen key.
• There was no significant change in the readout of the OSEMs related to the addition of mass (V1, V2 and V3 changed due to temperature change), and the oplev changed an yaw a little bit, which was expected. See this picture for the condition at the time of writing.
• I measured transfer functions of the IM and the system looks healthy.
• See details of the procedure in the notebook pages here and here.
• See the pictures in the album also.

The temeprature of BS and SR2 were increased during our work and went back after the work.

We suspect it caused by the LED lights and/ or KOACH filters.

One KOACH corresponds to ~ 200 W heat generator.