Week 16 of the Early Operations system optimization period
No nighttime observations were acquired with the Simonyi Survey Telescope this week.
Repair of the LSST Camera (LSSTCam) cryostat vacuum leak is progressing well. The team is executing the recovery plan developed last week, and has now successfully applied sealant to the previously identified vacuum leak area. The cryostat pressure fell quickly and stabilized around the baseline level, indicating that the leak is fully blocked. As the sealant material cures, the team is closely monitoring the vacuum pressure levels, and will execute a series of gentle movements of the telescope and Camera rotator, as well as filter changes, to confirm a robust seal under typical mechanical stress loads. Nighttime observations are anticipated to resume early next week.
During the week, the team continued studies to optimize the thermal environment and ventilation within the dome using the dome louvers and by varying the orientation of the dome aperture relative to the wind direction.
The maintenance downtime period that had previously been planned for March has been postponed until the Chilean winter 2026. Work during the LSSTCam recovery, as well as the recent demonstration of a new maintenance procedure, have alleviated the need for a full refresh (system flush) of the LSSTCam cryogenic refrigeration system during the next months. The team determined that other daytime engineering work that had been planned for March could be conducted in parallel with nighttime operations, or re-scheduled for mid-2026 when maintenance downtime could be better coordinated with other southern hemisphere observatories during a time of year with less favorable weather conditions.