On Tuesday 5th of February (yesterday) I checked the height of the optic again taking into account the information of the roll of the recoil mass (entry 7741).

Given that we decided not to compensate the bouyancy effect of all the GAS filters using F0 exclisively but to do it at each filter, I did the following in order to set the height:

• Set the BF LVDT to zero.
• Set the  F1 LVDT to zero.
• Set the F0 LVDT to -1.1 mm.

The -1.1 mm displacement of F0 LVDT accounts for the 1 mm we moved the system up with the jacks (old strategy to account for the bouyancy) and for the 0.1 mm the optic was higher w.r.t. Terada-san's reference. Given the roll of the recoil mass (RM), in this conditions the -X side of the (RM) should be 0.6 mm above the reference.

I took a look of the height usign the laser level and the reference and I saw the RM to be where I was expecting. Namely, approximately 0.6 mm above the reference. See picture attached.