Effect of Mirror Hatch Incident on Open Use Observations of Subaru Telescope (Report 3)
July 14, 2016
Subaru Telescope is planning works including the repair of the mirror hatch (Note) in multiple phases. Therefore, open use observations at the Subaru Telescope will be suspended from August 15 to 21, 2016 in Hawaii Time for seven nights. There may be additional downtimes between October 17 and November 6, 2016. These schedules might change according to the progress of the necessary work. The scheduled work of the primary mirror recoating is moved from this summer 2016 to 2017 or later.
Cause of the mirror hatch incident was due to the collision between the metal covers and the opening mirror hatch panel. The metal covers protect the rails on the mirror hatch, and were removed at the time of the incident while the scheduled maintenance work was taking place. The location where the rail covers were temporary placed overlapped slightly with the path of the hatch as it opens. The experienced staff was working on another high priority task that day, and it turned out that the instruction and the confirmation of the placement of the metal pieces were not sufficient.
Subaru Telescope strives to improve procedures of the relevant telescope work based on the cause and the details of this incident as follwoing:
- Paint the paths where the hatches move.
- Clearly states in the manual that, before operating hatches, make thorough inspection of the work area and relocate stuff if found in affected area.
- Review the safety prior to the operation of the hatches.
Note: Mirror hatch is on the floor of the telescope that opens to let the 8.2 m primary mirror of the Subaru Telescope go downstairs when it receives fresh recoating.
Figure 1: Location of the mirror hatch inside the Subaru Telescope's enclosure. (Credit: META Corporation Japan/NAOJ)
Effect of Mirror Hatch Incident on Open Use Observations of Subaru Telescope (Report 1)
Effect of Mirror Hatch Incident on Open Use Observations of Subaru Telescope (Report 2)