This was a big week for us. The Corrector optics and the Focal Plane Assembly arrives this week. Instead of the normal, mostly text blog, I thought I would just post a few pictures showing their arrival.

The Focal Plane Assembly, which will hold all of the guide probes and science fibers, arrives at the HET and is moved into the loading bay and then into the dome.

The Wide Field Corrector on its test stand in Arizona just before being loaded into the transport box.

The WFC in the transport box coming slowly up the mountain. It had a police escort and traveled 45 mph all the way from Arizona!

WFC arrives at the HET. We have to get it off the truck into the loading bay without exceeding the acceleration tolerances.

The experts from Crane Services lift the WFC over to the mouth of the loading bay. Then our expert sky track driver (seen earlier moving the FPA into the loading bay) moves it the rest of the way.

Much of the work in the last couple of weeks has focussed on the imminent delivery of the wide field corrector from Arizona later this month. We will have to test that the optical alignment of the corrector survived the trip down HWY 10 by placing it in a make shift clean tent put together in the loading bay of the the HET. This tent has two HEPA air conditioning units and a dry nitrogen purge line to keep the optics clean. Although it takes up most of the loading bay we still have just enough room to squeeze around it to allow operations to continue. See the picture below.

A panorama shot of the clean tent being assembled for the delivery of the Wide Field Corrector

Because of the slight delay mentioned in the previous blog post we have been looking at sub-systems which might cause further delays during the commissioning effort. This week we spent several days trying to increase the reliability of the communications in the CCAS tower and to shorten most copper cables and replace them with fiber where possible in advance of lightening season.

The night operations and software development teams continue to make progress on the Telescope Control System. Despite several weeks of delays due to poor weather we can now run trajectories on the sky with the tip-tilt camera and Distance Measuring Interferometer running to make refinements to the mount model of the telescope. We have also exercised the system with a few score of trajectories finding small bugs in the code well in advance of the bulk of the commissioning which will take place when the wide field corrector is mounted on the telescope in June.

In the last few weeks we have had an opening for a telescope operator. If you know of someone with a STEM (Science, Technology, Engineering and Math) background who would be excited by the idea of running one of the largest telescopes in the world and living in the the lovely Davis Mountains be sure to have them apply:
Positions open at McDonald Obs.

The big news from this week is that the review of the secondary corrector optics has completed. The review involved people internal and external to McDonald Observatory. The reviewers agreed with the WFU commissioning team that the corrector was ready to be shipped to the HET. However, they firmly suggested that the amount of knowledge transfer from University of Arizona to the maintenance team at the HET was not sufficient. Thus there will be a ~3 week delay in shipping the corrector so that the HET optical maintenance team can travel to University of Arizona and review the alignment procedures for future reference and in case of an unanticipated disaster in bringing the optics to the HET. This means that the corrector will not arrive in early May as planned but will arrive later in May.

The past three weeks have been dedicated to getting the telescope ready for various aspects of the upgrade. The mechanical and electrical teams have been trying to finish out various aspects of the VIRUS enclosures. The HRS has been stripped down to the optics table and the inside of the enclosure painted flat black.

The mirror team continues to pull the oldest mirrors in the array and replace them with freshly coated mirrors.

The night operations team continues to make sure that the alignment software is working well and is able to align all of the mirrors. Some tests of the telescope control system and mount models for the tracker motion have been tested. We now have pointing and tracking capability comparable to what we had before the upgrade began.

In the last few weeks one of our electrical technicians decided to retire. We have decided to change the position from a technician to an engineering position. If you know of an electrical engineer who is interested in living in West Texas be sure to have them apply:
Positions open at McDonald Obs.

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.