Today, Travis pulled the FC sheet on the BS optic, in prep for final SUS pointing measurements now that the SEI actuator housings have been attached. However, the sheet did not come off cleanly and there are numerous bits of very thin FC in the center of the optic, specifically where the thin windows were. As well, there is a full circle of haze where one of the thinner FC windows was pulled off at the 3 o'clock position. So, we sprinted to get the BS FC spray cone cleaned (no time for full class B at this point, but these are a tool that do not touch hardly anything so we're going with it) and will attempt a recleaning this afternoon. Note, I can't leave the FC sheet on because IAS/AOS need to see through the BS in order to look at the position of the elliptical baffle boxes (shown in the back ground of many pictures linked below).
Recall that the FC-HR sheet originating from CIT many months ago looked like this:
And here's after the FC was removed (using many minutes of N2 deionizing flow for particulate reduction):
And here's the picture of the ~3" circle of FC residue (???) at the 3" position. Interestingly, there was another 3" window at the center of this window and we could not see any such haze left from that window! There are also a few strips of FC shown at the edge of the optic in this picture.
Note, I do not anticipate the FC coning to go smoothly this afternoon since Margot, Kate and I ran into some issues with the small cone we used in HAM2/3 and this is a new unit which is being used for the first time for the BS.