Gemini North Shutdown Aug 10-31 to repair bottom shutter

The Gemini North enclosure bottom shutter experienced a drive shaft bearing failure in one of the two driveboxes during the night of July 27, similar to what happened to the Gemini North enclosure top shutter in 2014. The next day, the day crew locked out the bottom shutter at a position that has limited the telescope lower elevation to 38 degrees above horizon, while we continue to observe at night.

We will now move up the scheduled October shutdown, to be off sky from August 10 for about three weeks, to repair the shutter promptly. The planned work for the October shutdown on the Acquisition and Guidance (A&G) system and GMOS-North will be done during this time. We have agreed with the Canada-France-Hawaii to pick up the GRACES run (previously scheduled during this period) when we return to observing, extending to September 12. At the beginning of the 2016B semester, the queue is thin, so we expect minimal impact on global observation completion.