Nine weeks into the LSSTCam on-sky campaign. Weather-related dome closures limited test opportunities during much of the week in the wake of a winter storm that brought snow, ice, and multiple days of freezing temperatures to Cerro Pachón. On-sky engineering has resumed after the thaw.
New highlights this week:
- The team validated the procedure for routine daily calibrations, including pointing the telescope to the calibration screen, refining the alignment with the laser tracker, and running a script to collect biases, darks, flats, and a short photon transfer curve (PTC) run. The daily calibrations will be used to monitor the health and stability of the Camera during regular operations.
- Even with the dome closed, the team continued system-level “soak” tests with the telescope performing slews for a sequence of simulated observations. One such test ran for a full night without interruption.
- In Active Optics System (AOS) commissioning, the team tested an updated sensitivity matrix based on previous empirical measurements of the wavefront response to perturbations of individual degrees of freedom. The team also tested a refined elevation angle look-up table (LUT) for the open loop control control system.
- The team is now in the process of deploying the Feature Based Scheduler (FBS) configuration for the Science Validation (SV) surveys, and is poised to begin pilot observations at the next opportunity. Details of the enhanced SV survey design were described in a post earlier this week.
- The y filter was exchanged for the u filter in LSSTCam such that the currently loaded filter set is ugriz during dark time.
- Auxiliary Telescope (AuxTel) observations have been on pause for the past several months while the team has been focused on the on-sky commissioning with the Simonyi Survey Telescope. This week, all of the AuxTel systems were confirmed to be operational and ready to resume on-sky observations. AuxTel spectroscopy with the LSST Atmospheric Transmission and Slitless Spectrograph (LATISS) instrument will be used to measure the atmosphere transparency above Cerro Pachón.