In the last week we sorted out a number of small electronics issues with the tracker motion. These involved repotting components on boards, dry fittings, poor solder joints and one software bug. Once these were sorted out we were able to run tracks motions and slews in both axes. While this work was taking place the mechanical team finished putting the hexapod assembly together.

This week we will put on the hexapod test mass on the tracker to make sure that things move along smoothly. If that works well we will pull down the test mass and put up the hexapod assembly and start wiring it up.

During the last week they were able to communicate with all of the limit switches and sensors for the X tracker motion. Late in the week (including some weekend work) they installed the Y motors and were able to test that both the fine motion and the “antigravity” drive.

This week they hope to start integrating the motions in both X and Y as well as installing the end stops for the tracker hard stops. If all goes well they will install hexapod test weights late in the week and check that all motion is smooth with this extra added wait. Meanwhile some of the mechanical team is putting the hexapods back together.

Next week will be dedicated to getting the hexapods in place.

Last week we passed a significant milestone at the HET. We brought the tracker bridge out from Austin and lifted it into place. It went very smoothly and you can find a video of the lift at http://het.as.utexas.edu/wfu/.

This week we are cabling up the last of the X and Y cables. Then we will test the X motion of the tracker including the X-skew prevention under full closed loop control. Late in the week and extending into the next expect to start the installation of the Y drive system (including the so called anti-gravity drive). We hope to be able to gain back some of the two weeks of time we have slipped on the schedule by also putting the hex drive together at the same time.

Have a look at the link below for the promised video of the Last week’s work.

Cable Wrap Installation

Notice the use of hard hats in the dome (good safety practice) but it is harder to notice that everyone is freezing cold.

Last week we finished the cabling of the DAS box and populating most of the cables in the Azimuth wrap. We pulled in Resident Astronomer’s, Telescope Operators, the full day staff and even some people from McDonald Observing support. Thanks to everyone for the hours of hard work in the freezing temperatures. With so many people working so hard we neglected to take any photos of the work but I think we may try to put something together using the dome safety cameras.

This week we are getting ready for the new tracker arrival next week. This means we need to get the upper and lower X in full working order with limit switches in place, using the encoders for active feedback and have our emergency-stop system integrated into the new Tracker hardware. In addition to this work, we will be finishing decommissioning of the MRS enclosure to make room for the first group of VIRUS spectrographs to be shipped to West Texas sometime in the next month. We will have several different contractors on site this week. One connecting our large UPS system for the tracker, and another mounting the cryogenic lines from the site of the huge liquid nitrogen tank to the inner pier.

Last week we were successful in moving and aligning both the lower and upper X-slew axes. We also began the really massive task of cabling the tracker. Based on the rates of cabling we will likely be cabling until Thursday afternoon this week. This requires a team of ~10 people to connect the cable up at the DAS box and then down the cable trays, through the cable wrap, down to the spectrograph room and then through the spectrograph room cable trays into the lower electrical room.

Once the cabling is done we will start testing full motion of both X axes including limit switches and simultaneous moves of upper and lower x. All of this in preparation for the new tracker lift on the 18th (weather permitting).

Last week the team controlled the upper X screw for the first moves. The electrical team put the new Az wrap in place. Over the weekend we had a one-woman-team come in and paint the remaining weldments.

This week the mechanical team should finish getting the lower X components in place: encoder, lead screw, and energy chain. After those lifts occur the structure will be locked out and the temporary test cables will be removed and the final cables for the tracker will be installed. This is likely to take the rest of the week and perhaps the first few days of next week.

This will allow us a few days to test the upper and lower X motion both independently and working together in preparation for the New Tracker lift mid-Feb.