GeminiFocus October 2018 | Page 23

to warm up. We completed all the work in one day; the data center was brought back up, and the instruments recovered. Net re- sult: we reduced both the number of poten- tial points of failure and the overall cost of maintenance. Other issues addressed in this shutdown were the installation of improved encoder mounts on the elevation axis, checks on valves within the hydrostatic bearing sys- tem, and leak checking on the Cassegrain wrap Helium lines (one leak was found, and we swapped that line to a backup). On Friday August 31st, all systems were handed back for observing; although bad weather wiped out the first night while the team was having a shutdown party. All sys- tems were found in perfect working order, and all the instruments checked out (includ- ing GMOS after the bubble fix); the telescope is now ready for another year of operation. Every year, these shutdowns become more efficient and streamlined. Careful planning and attention to procedures and risk assess- ments are paying off in making this more and more a routine operation. A big thanks to all involved in making this a success! Gemini North Shutdown Underway Gemini North commenced its annual shut- down on Monday, September 17th. Work is progressing on several systems, includ- ing A&G issue follow-up and maintenance, Gemini Near-InfraRed Spectrometer cold- head refurbishment and other maintenance, GMOS VME hardware work, Near-InfraRed Imager and spectrometer Detector Control- ler troubleshooting, and Primary Mirror Con- trol System maintenance. Additional work planned includes enclosure bogie work and enclosure bottom shutter work, which will commence later in the shutdown. Big Island Mechanical, the contractor install- ing the Gemini North energy savings hard- ware, worked together with Gemini day crew to move the new Chiller 2 modules into the Exhaust Tunnel and onto the vibration isola- tion frame. Gemini is also temporarily shut- ting down the Chiller 1 cooling water circuit during the shutdown so that Big Island Me- chanical can cut into the existing piping to install new hardware. Figure 10. Performing maintenance on the Science Fold mechanisms in one slice of the A&G unit. Credit: Joe D‘Amato 21 GeminiFocus October 2018