This is Week 9 of the Early Operations period for system performance optimization prior to starting the 10-year LSST survey.
Environmental conditions at Cerro Pachón have been less favorable this week, with heavy clouds and high dew point temperatures delaying the dome opening or requiring full-night closed-dome testing on several nights this week. During the periods with acceptable conditions for on-sky testing, the atmosphere seeing was less stable, and some of the planned tests for Active Optics System (AOS) have been postponed until the conditions improve. Still, the team ran further tests to diagnose the apparent time-varying filter focus offsets, open loop stability tests, as well as a functionality test for a machine-learning based wavefront estimation pipeline. A high priority for the next opportunity with good atmosphere seeing is to complete data collection for the elevation and physical rotator look-up table (LUT) for a combined set of hexapod and mirror bending mode degrees of freedom by running the AOS closed loop to convergence at a grid of elevation and rotator angle coordinates.
The second major on-sky activity for the week has been running pre-LSST observations with different Feature Based Scheduled (FBS) configurations, with and without intra-night filter changes on different nights. Over the next week, the team plans to run several full nights of pre-LSST observations to benchmark the current performance, including the distribution of delivered image quality and effective survey speed for sustained survey-mode operations.
A filter swap to remove u and install y occurred on 23 December such that the current filter set is grizy.