Gemini South Shutdown Completed

The annual telescope shutdown is now complete at Gemini South with the main objective achieved – to resolve two outstanding faults on the acquisition & guidance unit (A&G). First, one of the wavefront detectors which was recovered thanks to an in-situ cable repair and second, the linear slide mechanism of the science fold mirror was recovered by installing a new encoder. As a preventive measure all pulleys and belts that drive the science fold linear mechanism were replaced. Apart from these faults (that were affecting regular observing) preventive maintenance was performed on all mechanisms, optical elements were cleaned, and the entire system was thoroughly tested using a large battery of tests. Under our Operations Improvements Program, progress was made on characterizing the A&G vibration environment by confirming that some of the high frequency vibrations are caused by the servo loops and not by external interference.

On October 12th, the A&G system was tested again on-sky, in order to resume regular operations on the following night. Reducing the scope of activities was critical for the successful completion of those tasks that require interruptions to our operations. This time around it was even more important given the critical final integration phase of the Toptica laser, which also required resources. Overall, excellent coordination between the teams led to successful completion on both the laser and A&G work.