1 Progress for July 19, 2011 Preparations for Fill. –4 protection valves were attached: 2 on Z-shaped tubes, 2 on the tank –Herman’s new CTIO engineering analysis docs are in Tank Pressure Relief Regulator sets operating pressure Vent Side

2 Progress for July 19, 2011 Preparations for Fill. –Proper actuation of the valves was tested using the LabView software. (See right upper & lower). The challenge is to find difference that indicates the valve moved. –Operation of the O2 sensor in the Coude Room was tested. It closes the valves in the valve box if O2 level is low. (See below.)

3 Progress for July 19, 2011 Fill to ~12% was done in 2 steps from a single CTIO Dewar. First trained Jorge and Javier, then Gale and Mauricio. It took 50% of the CTIO Dewar to make it that far, but much of that LN2 was vented to cool down the Tank. The tank is left at this level for the night. Tomorrow the cool-down of the Jorge loop after La Serena observers arrive from down the mountain.

4 Progress for July 19, 2011 Other –Boxes on ground floor marked for movement later in the week. –Still running the labView PC on network 13. For some reason I think the planned IP was –CTIO computing/networking people are deciding what to do about networking and IP addresses. Demonstration of “RTD connector” Rupture disk on Tank Jorge and Andy

5 “Action” Shots

6 More “Action”

7 Next Steps & Plan Cool down tomorrow (Wednesday) after 10 AM –Make sure we protect the stuff in the Coude Room from the iceball that will form at the LN2 supply-return bypass “Jorge loop”. –Check RTDs on cryocooler and Tank. Confirm the pump rotates in the right direction and that the LN2 heaters inside the Tank turn on. –Cool-down after lunch with CTIO experts-to-be. We still need to sort out the computing network problems with the relevant expert(s) on-hand. We still plan for come down to La Serena on Thursday. Herman, Andy, and Rolando leave on Friday. Things to go up to M-floor before Ken Schultz, Cheryl Jackson, and Steve Chappa arrive: Filter Changer Shipping Crate and HexaP0d rack and cables and then the hexapod itself. Hopefully Friday.

8 End of July 19, 2011 Serge Dieterich (GA State. U.) Showed us the 0.9 m telescope last night Shadows of Cerro Tololo domes at 17:20 7/19/2011. The shadow of the 4-meter is on the right.