As announced, on Thursday 24 October 2024, on-sky data taking began with the engineering test camera for commissioning (ComCam) installed on the Simonyi telescope. In a complicated system, many hardware and software systems must work all together. Decades of effort paid off: the telescope optical alignments were remarkably close to optimal before even looking at the sky, with the ComCam focal plane within about 1mm of being in-focus, and the initial model for gravity-induced distortions of the mirror, which are compensated by the active optics system (AOS), was enabled and used to refine the focus and alignment. The system was soon delivering a total image quality around 1.5 arcsec, even with most of the optical adjustments and environmental controls not yet fully in place. The Data Management system has successfully processed a subset of in-focus images through single-frame measurement to provide initial astrometric and photometric solutions for individual visit images within minutes of acquiring the exposures.
We have many months of effort and challenges ahead, but the experience during the first week of ComCam on-sky commissioning bodes well. The highest-priority activity of the coming weeks is to commission the AOS so that it runs automatically and reliably in this real environment.