The last two weeks have not seen any obvious large changes to the facility. Some of the team continue to work on the VIRUS enclosures and their annex. The Annex is where much of the breakers, electronics, fans and junction boxes are located. Other members are sealing/caulking the seams of the enclosure so that when we close it up it will be air tight.

We did have some contractors on site finishing up a few punch list items from our remote thermal area project including a team from Trane came out last week to setup some of their communication hardware and test the glycol temperature control system as far as possible without a load on the system.

We painted some test squares of ultra flat black on the High Resolution Spectrograph (HRS) enclosure in preparation for the beginning of its upgrade.

The mirror team has swapped 4 mirror mirrors in the last two weeks keeping on schedule. They continue to make some improvements to the Strip and Wash room including installing a 2nd hot water hose in strip wash area and adding acid proof shelving.

The at angle tests with the wide field corrector at the University of Arizona are going well. So far all deflections detected are elastic and within specification. We are going to have a final review of the corrector alignment with several external experts in early April to get the final ok for shipping the corrector to the telescope.

This past two weeks have been eventful. Most of the prior week was spent trying to get the VIRUS enclosures and cryogenic safety systems online for the first delivery of liquid nitrogen into our big tank. This involved installing lots of cryogenic lines and one large LN2 tank on each of the VIRUS enclosures.

Although a few last minute alterations had to be made, the filling of the tank went smoothly. A single truck can not fill our tank but we did put in 4,000 gallons of LN2 into it. Much of this liquid would be burned off quickly to cool the tank and all of the cryogenic lines that lie between the tank and the VIRUS enclosures. Just for reference the cost of very pure LN2 trucked out to W. Texas is about a dollar a gallon.

The contractors for the tank and cryo-lines lead a safety class for the staff and we reviewed all of the alarm and oxygen sensors now placed around the facility.

The mirror team continues to swap freshly coated mirrors for the mirrors with the oldest coatings. This past week they swapped 4 mirrors.

We have installed an in-line filter for the fan venting the CCAS tower. This filter will allow us to reverse the fan and run it continuously during the day to keep the tower close to ambient temperature. The software group has finished a prototype piece of code that will turn off the fan just after sunset or if the weather conditions indicate a “close all domes” condition such as high humidity or dust.

The wide field corrector is undergoing extensive “at angle” testing to make sure that the alignment can be maintained between the assembly and shipping vertical axis and the 55 degree angle that it will live at in the tracker. These tests are being done at University of Arizona. When done the corrector will be put into a special shipping box and sent to W. Texas on a special air-ride truck.

As mentioned in the previous post in the week of December 8 many of the staff were working off the facility. This week most everyone is back on site.

The team who went to Texas A&M had a very busy week. They soldered glycol lines, installed covers and tested the system under pressure. They found some leaking at 40 psi and at 80 psi the leaks were severe. The team left it back in the hands of the A&M engineers for them to fix these severe problems. The 2nd VIRUS enclosure is supposed to go on the telescope in January and at that time we would like to do an end to end test of the chilled glycol system.

The team who went to Germany for the HET board of directors meeting brought back good news. The board was pleased to see the progress that the operations team is making and authorized the use of some operations funds for the wide field upgrade to make sure that the teams in Austin and West Texas have enough personnel to stay on schedule for a summer time first light. They were also impressed with the latest installation video, the nitrogen tank installation. Please have a look at: https://www.youtube.com/watch?feature=player_embedded&v=2a1xZF1b0wQ.

The groups that were not traveling have been busy as well. The work on the Anemometer project has drawn to a close. We are collecting data. The next step is to start visualizing the data and actually trying some experiments with louver positions with respect to wind and dome position. This will be a longer term effort.

The night staff have been optimizing the stacks and are now able to get stacks of less than 0.5″. The software team worked this last week to set those optimizations as the default in the stacking code.

An engineer from Austin came out this past week to begin the installation of a clean room for the much anticipated WFU corrector. This huge 4 glass Spherical Aberration corrector will be brought in from University of Arizona on a special truck that will minimize vibration. Even so, when it does arrive it will have to be tested to see if it is still in alignment. This will be done in a clean room tent we are constructing in our loading bay. This will take up the majority of the loading bay for a month and will stop us from receiving any large shipments for the dome floor. This week the frame for the tent went in.

Even over the holiday break we will continue to get some work done. The contractors working on the remote thermal area will be receiving and installing the glycol chiller on site on December 30th. The system probably will not be fully ready to go until mid-January when the 2nd VIRUS enclosure is installed.

Since last week included a holiday we will include activities from the last two weeks.

This week we had a software engineer from Austin visiting to commission the Metrology loops in software. The includes the distance measuring interferometer, the tip-tilt sensor and guiding with the CAT. The team was able to accomplish all of these at a single azimuth but problems with the alignment of the CAT stopped further exploration of the performance of the system. We will test the alignment of the CAT on Sunday so that further commissioning can continue.

In the previous blog post we mention the discovery of some loose bolts. The source of the “loosening” is still a mystery but we installed an accelerometer to look for significant jarring events on the tracker. This week we took it down and looked at the data. The most serious events were those of the installation and removal. Even forced Emergency Stops did not produce large accelerations.

Commissioning of the Strip and Wash Room continues. The room heater and make-up air were tested and found to work but needs small tweaking with regards to the indicator lights on the controls. Other members of the team are working on the Safety Protocols document. They believe that commissioning will be completed by January 5th and that we should resume mirror swaps in the primary at that time.

This week one large project has been completed. Phase I of the Dome Sealing and Conditioning was completed with the last of the dome “hair” seals being refurbished. With the completion of Phase I we have sealed the vents on the ring wall, refurbished the seals at the base of the dome, sealed the leaky dome nodes and replaced all of the louver seals. We note that this last rainy season we did not have any leaks in those locations. Phase II involves sealing the dome shutter and will require some engineering.

The technical teams at the HET continue to make progress on various projects such as continuing installing the VCS Safety System components; installing a differential thermostat and a parallel temperature acquisition system in the K-Hut to monitor inside and outside temperatures over the weekend; and test fitting the PFIP Electric Box Frame Weldment Assembly. One pending item that was accomplished was to replace the structure drive wheels. These wheels were showing considerable wear and we replaced them before a failure could occur.

The Anemometer project has made some progress this week. All of the units were calibrated and the system was run over night on Wednesday and Thursday. Some problems were found in shared memory flags in the database but these were cleared up and we should be able to start collecting data and looking at how to best visualize and utilize this new data set to minimize dome seeing induced by turbulence.

In the coming week we will be down a large number of staff. Three of the operations team who are traveling to Texas A&M to speed along the final assembly and testing of the 2nd VIRUS enclosure. Three other people from the operations team (including the blogger) will be traveling to Germany for the HET Board of Director’s Meeting. Much of the last two weeks was spent in preparing reports and presentations for this meeting.

Work continues on various aspects of the new tracker. In the electrical room one of our E. techs installed a new
Phase Control Modification circuit for the LER Servo Driver cabinets and successfully tested its operation. This will be critical if we were to loose just one phase of power. One of the other E. techs and a programmer from one of our partners in Germany have started working on the VIRUS enclosure PLC for monitoring the sensors within the enclosure. They tested each sensor and mute switch; all worked as expected. End to end testing will be done next week. Meanwhile the mechanical team worked on the Platforms for the first Virus Enclosure. It took several days but all of the platforms are now in.

After the interruptions due to weather and the problems of the loose screws from last week we are finally back on sky this week. Night operations commissioning started with the first data sets for structure and tracker sag models. This is done with the small celestron telescope mounted on the tracker. After the engineering tasks were complete,
the telescope operator was able to find all of the mirrors (with some assistance of the mirror team who sited some of them in from the catwalk). Mirror alignment for the full array is now near 0.5″.

Work continues on the commissioning of the strip and wash room. We finished working on the PID control of the strip/wash room exhaust fan. Fan will now respond to pressure setting change requests from within the strip/wash room and regulate the pressure to previously established set points. This will allow the team to switch from positive pressure while washing or drying mirrors to negative pressure when doing acid stripping.

We reviewed spectrograph room temperature data and discovered that we have dropped below the cooling temperature settings of the Mitsubishi thermostats/control heads, this is largely due to the thermal pulse moving through the ground produced by our <20 F temperatures last week. We have designed a new experiment to determine the optimum method to hold the 16 C setpoint during periods where both heating and cooling are required. We hope this new methodology will work. If not then we will need a PID controller which will require significant more work.

Our electrical tech began work on Virus enclosure this week. We will be installing all of wiring and breakers in the enclosure. One of our telescope operators is working with one of our programers to sort out the remaining problems with the wiring to the anemometers. The next step will be to set the zero point of the wind vein in the software which requires them to point the anemometers in a known direction and note the position read out. We also installed a new digital rain gauge this week. We will now be able to record when we have rain events in the weather archive. Work on the TCS continues and some bugs in the RA and DEC offsets were found and removed. Offsetting in X,Y, rho are still to be done.

This was supposed to be the last week for work on the Facility Thermal Management Project. Veliz Construction finished the back stairway past the K-hut to the liquid nitrogen slab. This was a requirement by the people who will be filling the liquid nitrogen tank. A fair amount of time was spent putting insulation around pipes, cleaning up the site and small projects. The consulting engineers from El Paso came out on Thursday to generate the punch list of remaining items for the contractors.