Rubin Observatory is now 8 weeks into the on-sky commissioning campaign with LSSTCam. We had the first snowfall of the season. Even with several nights of weather-related dome closures, the team made progress in multiple areas during the week.
New highlights this week:
- The team completed fine balancing of the Simonyi Survey Telescope. While the telescope mass is roughly 350K kg, a single person could move it with their hand (if given permission to do so).
- In Active Optics System (AOS) commissioning, the team validated the automatic refocus capability that allows the system to recover from out-of-focus conditions within +/-1.5 mm, i.e., as long as the focus offset is within the range of the wavefront sensors. The team also has prepared an updated elevation look-up table (LUT) for the AOS open loop control system. Work continues on analysis of the sensitivity matrix and reference wavefront data.
- For calibrations system commissioning, the team is now using the laser tracker alignment system to bring the flat field projector, reflector, and screen into an optical configuration that can be repeated for consistent night-to-night measurements. The team used the flat-field system to acquire photon transfer curve (PTC) range data, gain stability data, and a full set of single-LED flats with and without filters. Commissioning of monochromatic flats began this week. In this mode, the same tunable laser source as used for the Collimated Beam Projector (CBP) is instead used to illuminate the full flat field calibration screen in 1 nm wavelength increments to produce monochromatic flat field measurements.
- Rubin Observatory is preparing to start pilot observations for the Science Validation surveys. This week included nearly all-night tests using the Feature Based Scheduler (FBS) to drive wide-area observations in a mode similar to the LSST Wide-Fast-Deep survey to examine the distribution of delivered image quality and characterize the overall operational efficiency while quickly scanning the sky. The team has converged on a candidate scheduler configuration to use for the start of Science Validation Survey pilot observations.
- The currently loaded filter set is grizy during bright time. A filter swap to exchange y for u is planned for next week.