Category Archives: Instruments

Here we comment on the Different Instruments for the HET

The week of Nov 10

The biggest change the occurred this week was the completion of the HPF enclosure. A team came out from Penn State to lead the efforts and after two days the enclosure was completed and the last day was spent wiring up temperature sensors to monitor how the systems reacts to seasonal changes in the HET basement.

Newly installed HPF enclosure next to the HRS enclosure.

Newly installed HPF enclosure next to the HRS enclosure.

Our electrical team completed hook up of power cables to distribution boxes in Virus annex this week. They hoisted and installed the Virus equipment rack in the annex as well. We hope to have all of the electrical work done for the first enclosure by the end of next week when a programmer comes from Austin work work on the PLCs.

This week we found a problem with loose screws on lower X. We shut the tracker down for the week and an engineer came out from Austin to inspect the system for any damage. He found that many of the screws were loose and some of the shims were missing. This was likely caused by a fairly strong vibration incident that we had when we were commissioning the TCS timing loops. The engineers and mechanical team got the X drive shimmed and aligned again and all of the crews have been tightened down with torque wrenches. While the engineer was out here he worked on the rho stage which was hitting the proximity sensors early due to the non-flatness of the switch plate. They re-installed it with shims to adjust flatness and installed RHO limit switches and set the clearance.

The initial commissioning of the Strip and Wash Room began this week. A mirror segment was put through the new ultra-pure water cleaning. It is not entirely surprising that a number of small leaks were found around the mirror and passage way doors. The rest of the week was spent finding leaks and diverting water drainage paths. Our electrical engineer has nearly completed the PID controller and pressure display that will show when the room is in positive pressure and negative pressure.

As an interesting diversion this week we had the Director on site with several photographers taking pictures of him and the facility. Some of the shots were done from a helicopter while others were done from various catwalks or man-lifts. We all look forward to seeing these glamour shots.

The week of Nov 3

The in-line fans for the K-hut and Strip and Wash room are now in place and working. This means that we can begin the process of commissioning the strip and Wash room. At the moment we still need a few more safety indicators on if the room has negative or positive pressure and to get the hot and cold water nozzles in place. This work seems to be moving forward at a good pace.

The replacement of the old truss sensors is moving forward. As mentioned before the old sensors have been removed and the new ones are being assembled.

Lift 3rd VSS platform into place, test fit, secured in place in prep for install.
Moved upper VSS platform into bay area, painted modified area and moved onto dome floor.
Work around the VIRUS Support Structure (VSS) continues. We have made some modifications to the work platforms and three of those have been test fit, secured in place and in preparation for the installation in two weeks. This week we did some work on possible coupling between the VSS and the structure. Our concern was that wind shake on the VSS would cause the mirrors to move. We did a number of test at the CCAS tower involving people physically moving the currently empty VSS enclosures. The concern seems to be warranted as the FWHM of the induced movement is about a quarter of an arc-second. We will look into identifying the members that cause the most coupling between the two and mitigate the motion.

The software team out here has been working on the DMI and Tip/Tilt to get it realigned with the new mount models that were installed last week.

The big news this week is the arrival of the HPF enclosure. Despite some very thick fog and misty rain we were able to get the truck unloaded and placed in the spectrograph room without tearing up the newly prepared floor. The PSU assembly team will arrive late next week.

The week of Oct 27

The contractors continue to work through the Remote Thermal Area punch list including
repairing sheet rock, cleaning up building penetrations, clean up material and reinstalling the roof gutter down spouts. We also have contractors out working on the balance of the in-line fans for the strip and wash duct and the K-hut duct.

We received another shipment of VIRUS Platforms/Ladders;
it contained the platform side supports for both VIRUS right and VIRUS left and a top work platform for one of the VIRUS enclosures. We have been doing test fits of these enclosures in preparation for installing all of them in two weeks.

John Good, mechanical engineer from Austin, was here for the last two weeks to work with the laser tracker. The first days were spent confirming the current mount model then making refinements to it. We now believe we have the best mount model that can be obtained with this laser tracker.

Some work at night was done this week. We went on sky to test the mount model, see if the position of the Celestron Alignment Telescope (CAT) was good enough for future testing. We found the RA, DEC and rho offsets are now working and that the center of rotation falls at the corner of the CAT. Tests of the geosynchronous satellite tracking software within TCS suggests that it is probably working although the CAT is just to small to see these 11-13th mag objects. We believe we are sufficiently ready for any future metrology tests. With this alignment out of the way we put the CCAS tower mirror alignment system back together and have confirmed that all of the components are well aligned and working with alignment to better than 0.5″.

Work in the spectrograph room continues. One of our TOs finished the touch-ups required after the contractors scratched the paint in the area where the HPF enclosure will go. With that done we are ready for the HPF enclosure to arrive next week. We also received the mounts for the HRS sensors. These will be part of the system that monitors and controls the HRS temperature to improve performance in velocity stability.

The really big news is that we installed the large liquid nitrogen tank behind the K-hut. This required days of preparation and coordination between the HET, Crane services, Praxair and Midwest Cryo teams. The two cranes made quick work of putting the crane in place and by lunch the tank was bolted down. In the two following days nearly all of the plumbing to the K-hut vaporizer and the filling location were installed.

DSC_0061

The week of Sept 15

The big news this week is the installation of the first Virus Enclosure Unit. This large black structure came out on two 45 foot trucks and took two days to lift into place on the side of the telescope using the dome crane. It is roughly two stories tall and 5 feet wide. A very impressive structure that really changes the character of the telescope. In the coming week we will be adding the electrical components and a few more plumbing components. The second Enclosure will be delivered at the end of Oct.

A picture of the 1st side VIRUS Spectrograph Enclosure being installed on the HET.  In the picture the team is busy installing the last section, the Top Annex.

A picture of the 1st side VIRUS Spectrograph Enclosure being installed on the HET. In the picture the team is busy installing the last section, the Top Annex.

The software group came out to the HET last week and were able to close the loop between the DMI, tip/tilt camera and the TCS. Unfortunately, problems with weather kept them from making a progress with the CAT on sky. This week has not been any better. The telescope has only been open for very brief periods for the last two weeks; not even enough to complete an alignment of the primary mirror. Getting on-sky will be a priority for the coming weeks, although the CAT will likely be moved from its present location to the center of the rho stage so that we can do more extensive guiding tests on the sky.

The Mechanical and Electrical contractors have made good progress of the last two weeks. The air-conditioning units for the upper electrical room and the spectrograph room have been removed and replaced with new units that make use of the large units out at the remote thermal area. This work has not been completed and these areas are currently without cooling for the next week until that work is completed.

The work on the vault to the remote thermal area has essentially been completed including putting the steel plates over much of the vault and pouring a new water drain over these plates. The pylons for the Krabbenhut heat removal have been finished and they are currently working on getting the acid vapor brackets in place.

The dirt work contractors have completed covering up the lines out to the remote thermal area and have started digging down to move the water line that is below the future location for the liquid nitrogen concrete pad.

The week of March 31st

In the past week the HPF team from Penn State came out to remove the last components of the MRS and install the calibration enclosure for the HPF. This work went well and their enclosure is now in place. They have approved the floor paint which will go below the HPF main enclosure when they bring it out in late 2014 or early 2015.

We also made a jump forward with the mirror Strip And Wash (SAW) room. This room is connected to the mirror coating chamber and now we can do a final ZrO strip of the surface and a ultra pure water rinse and take it directly into the coating room without leaving a clean room area. This SAW room is now being used in a very manual mode and we hope to automate some components in the future.

This past week we made some small improvements in the tracker performance but we continue to have problems with the encoder. We will continue to work on this problem this week.

This week may be a little slower until we can get the problems with the tracker fixed. This will give the operations support team a chance to catch up with maintenance issues and make progress on other projects like the mirror washing room.

We also may have some contractors for Veliz Construction on site to begin the process of aluminum taping of the control building roof. This will reduce its emissivity and should help it from super-cooling at night and sending cold air into the dome. Unfortunately for Veliz the wind does not look like it will give them much of a break to actually get the work done.

The week of March 24

It has been slightly slow going with the new track electronics. We have found that some communications are flaky (bad mil-spec connections) and many of the motors require significant retuning. The PFIP test mass is in place but we want to make sure we have all motions largely tuned and reliable before we pull down the test mass and replace it with the hexapod assembly and the PFIP frame.

We have had several pieces of bad new from the University of Arizona group who are assembling the HET corrector. At the moment we have had a slip in the delivery date of three weeks and may see further slips in the near future depending upon the nature of the problems they have encountered.

Later this week the HPF team from Penn State will arrive and will be shipping out the last of the MRS and FIF components and assembling the calibration enclosure for the HPF.

The week of Feb 17

Last week week we finished clearing out the optics tables and floor for the MRS decommissioning. We also met with the HZPF team to discuss their preliminary plan for their new enclosure in the spectrograph room. Much of the staff were preoccupied with finishing preparation for the tracker lift. The crane arrived late on Friday afternoon (3 days early).

This week the Crane Services will setup for their work on Monday and will take out the lower and upper X rails that were used for shipping. We are now done with them (since the lower and upper X components are assembled and working on the telescope). On Tuesday the tracker should arrive from Austin in the morning and if the weather cooperates Crane Services will lift it into place. We expect that this will take much of the day. We hope it does not take longer because the winds are predicted to rise on Wednesday and peak at “Destructive Winds” on Thursday. Once the tracker bridge is in place we will begin cabling it and start testing moves over the next weeks.

The week of Jan 6

Just before the winter break we had the Physical Plant team and some of the HET staff work on taking down the walls and roof of the MRS enclosure. The MRS is being stored away and that space will be used in the next 8 months for storage of the VIRUS units as they begin to arrive. We still have to remove the huge optics benches and the floor of the enclosure but once those are out we will be ready for the first VIRUS unit to arrive in West Texas by the end of January.

Work continues on putting components of the lower and upper tracker drive assembly in place. All of that work needs to be done before the new tracker can arrive. The original scheduled date for the tracker to arrive was the week of Jan 27, as see in the gantt chart blogged on August 12, 2013. We should be able to make this milestone without any delays.

The electrical and mechanical contractors worked over the Christmas break to try to make up for delays earlier in the planning part of the project. We now have 480 V power in the lower electrical room and the trenches cut in the concrete dome floor are in place ready for the liquid and vapor nitrogen lines.

Happy New Year all; it looks to be an exciting one!

The week of Oct 28

In the past week we finished most of the work on the Virus Support Structure (VSS) and on Friday were able to have the first rotation including the new air bearings under the VSS. In addition, we had some of the team working on sealing the dome enclosure. Vicki worked on the outer vents at the base of the ring wall and Logan and Kathryn worked on the dome and sealed the nodes near top.

DomeNodes1

This week we will be finishing the clean up of the upper hex removing the trollies, encoders and last of the interconnects. We will also make room for the new JLG man-lift (we call Jr.) on the dome floor. This work is in preparation for the work that John Good will start in Nov.

The week of Oct 21

This past week we worked on getting the Virus Support Structure (VSS) cross supports and over-turn preventers welded into place. Other activities included test digs around the location of the liquid nitrogen tank and the vault for the remote thermal area, setting up the air system for the VSS and continued work on the cable-ways for the lower electrical room.

This next week we should finish the VSS work which means that we should be able to unlock structure rotation. If all goes well we will now have the Structure firmly welded to the VSS and they should rotate together as if they were one system.