We did some simulations of data transfer rates in preparation for VIRUS coming on line. The data set consists of 900 fits files; each file is 8524800 bytes in size. The working assumption is that one Hetdex image consists of 150 spectrographs x 2 amplifiers/spectrograph x 3 dither per field with a CCD size of 1032×2064 pixels. Total data size is 7,672,320,000 bytes (7.3 GB). The data would be collected over 20 minutes (~6 minutes per dither) but it only took 449.5 seconds (7.5 minutes) to transfer this data to Austin. Thus we should be able to keep up with the data collection rate without bringing the network to a crawl.

The large air and glycol (“Blue Thunder”) hoses were installed through the Az wrap and laid in the trench in the floor and through one of the ports through the pier to the ring wall in the last two weeks. The next step will be to connect these to the outside lines and do a pressure test of the system.

All power connections for the VIRUS enclosures are now complete and tested. We have also conducted some heat load tests on the liquid nitrogen system by placing plastic bags over each of the VIRUS bayonets (the component that will stick into a VIRUS unit to keep it cold). So far most of the system checks out close to specification.

The primary mirror group installed 4 mirrors this week and continue to keep up their 30% over expected swap rate in hopes of being close to completion when the corrector is ready for commissioning.

The CCAS shutter failed this week and could not be repaired from inside the CCAS Dome. Instead of having to rent a very expensive 90 ft manlift the mechanical team found a way to safely undo the mounting to the CCAS Dome and lower it to the ground. A replacement shutter is on order and should arrive in the next week or two. It will be installed by just reversing the procedure developed to remove the old shutter. Until then we’ve installed a simple wood plug that can be removed manually (after climbing the 90ft tower) to continue with critical primary mirror work.

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.

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.

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!