This week John Good, a mechanical engineer in Austin, is back out to run the 97 point test to characterize the shape of the sphere that the tracker traces out above the primary mirror. Several weeks ago we attempted to run this test but found that the number of measurements we were taking per point was to many and we were only able to get a 21 point test. This time the tracker is running more reliably and we are going to take fewer measurements per point. This test will be conducted at night and we expect it will take 3 nights.
We no longer need the four mirrors that we removed from the array for laser tracker work. The optics team will begin to replace these last 4 mirrors, at which time we should have a fully populated array.
The mechanical contractors on site continue to work on the pipes in the vault. This week they will be putting insulation around the pipes. The dirt works contractors are working on the base of the piers which will hold the acid vapor from the strip and wash room and heat ducts from the Krabenhut.