In the past week we had great guys from Crane Services out to the HET to remove the old tracker bridge from the dome, move the new lower X and upper X assemblies onto the dome floor, and move the VSS into place. It all went very smoothly and they finished on Thursday about 1 hour before a small windstorm (by West Texas standards) moved in.
There are numerous pictures taken by:
Dave Doss of the Old Tracker lift
Dave Doss of the VSS installation
and here is a picture of the tracker removal taken from Renny Spencer who was purposefully stranded up on the upper X beam to monitor the lift.
There is even a movie produced by Eusebio Terrazas:
This next week we will be tuning up the VSS, putting in the diagonal bracing and getting ready to hook it up to the air bearing system. Other work at the HET includes putting in cableways in the lower electrical room and spectrograph room, stripping the old coating from the primary mirror segments that were removed before the upgrade began, and applying extra sealant to the dome nodes.
Last week we finished the painting of the CCAS tower and the removal of the equipment on upper X hex.
This week we will expect a crane to arrive on Monday and from Tuesday through Friday we will be removing the old tracker bridge, install the Virus Support Structure and stage the upper and lower X rail assemblies for the new tracker onto the dome floor. The upper and lower X rail assemblies will be shipped from CEM in Austin to McDonald on Monday so that they will be on site Tuesday morning. The road to the top of the mountain will be closed to non-essential personnel.
We are still on schedule.
In the last week the first components of the WFU went into place. We are currently right on schedule.
This week we will be clearing out the last components at the top of the tracker, finishing the removal of any old interconnects on the ground and prepping the dome floor for the next big crane lifts in the following week.
Also we will have painters out at the HET site repainting the CCAS tower white and painting the side of the tower that faces the mirror flat black. Hopefully someone will have some before and after shots of this work.
For this week we have two priorities: 1) we are in the process of cleaning up the upper and lower hex, specifically the lower and upper rails that the old tracker rides on and 2) we are putting in the VIRUS cross support structures. This cross support structures are really the first (of many) pieces of the Wide Field Upgrade equipment to be installed at the HET!
Please have a look at http://het.as.utexas.edu/wfu. This site has some very nice movies from the last month of the West Texas Wide Field Upgrade preparation work, including the mirror removal, net installation and the removal of the PFIP.
Information about the VIRUS instrument and how it will be used to conduct HETDEX can be found at this link.