Last week the certified welders finished up work on the X-rail stiffener and the supports for the lower X work platform. Logan was able to strip the M4 witness sample with a fairly simple Greenriver solution.
This week we will have our local welders finish up with the tracker weldments. We will also be working on the cable trays that lead from the cable wrap up the telescope structure toward the tracker.
While working on the alignment of the corrector at UA, out team found that the coating on M4 (and a few of the witness samples that came with it) was beginning to have signs of coating failure, bubbling and spotting. Our current plan is to send the witness samples to McDonald so that we can confirm the stripping process for this very tough coating and then send that witness back to UA so that they can confirm that the witness has not been damaged. Meanwhile UA will continue to work on the corrector alignment with M4. If all goes well we will then strip the coating from M4 and send it to be recoated once they have all alignment issues worked out. The question remains about who will do the recoating.
We hope to act quickly and get M4 back to UA for final alignment before shipping to McDonald in the spring.
So far this does not pose an imminent threat to the WFU schedule.
Last week we finished up the metrology measurements of the upper hex and all of the cableways in the lower electrical room and spectrograph room.
This week we will have welders on site working on the channels for the lower X stiffener and also the new work platform for the outside of lower X. We are also taking apart the MRS enclosure for storage, reshelving the Az cable wrap and installing static cable wrap. We continue to be on schedule.
In the past week we finished cleaning up the upper hex. In the process we had to move some of the cameras around in our internal views of the dome so the view located at:
http://het.as.utexas.edu/wfu might look a bit strange until we get around to moving the cameras back into place.
This week we will be starting the metrology of the upper hex in preparation for putting on the upper and lower X rails. This metrology is done with a laser tracker and small “nest” mirrors placed around the telescope structure. Other activities this week will include finishing up the cable-ways in the lower electrical room and spectrograph room, work on the structure azimuth cable wrap, and work on the static cable ways. It is amazing the amount of power wires, optical cables, glycol and air lines that need to be strung up.
We are still right on schedule.