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The Vera C. Rubin Observatory's Simonyi Survey Telescope (Simonyi Telescope) is an 8.4m telescope now in the integration and testing phase, on Cerro Pachon in Chile. To fulfill the Rubin Observatory scientific objectives of conducting a decade-long time domain survey of the optical sky, the Legacy Survey of Space and Time (LSST) \cite{Ivezic19}, the telescope requires delivering a consistent exquisite image quality over its 3.5 degrees field of view (FoV). This is accomplished using a sophisticated active optics system (AOS). In addition to correct the predictable static and gravity induced aberrations in open-loop, there are four curvature wavefront sensors (CWFs) at the periphery of the detector. These CFWs allow to calculate, in quasi-real time (40s), the appropriate correction offsets to be sent to the three Simonyi Telescope's actuated mirrors and the two hexapods, to further improve the image quality.
In this paper, we describe the algorithms optimization and trade-offs, including the use of PSF moments variations for telescope alignment as well as wavefront error estimation. To validate these studies in advance of on-sky testing, we are using both a simulation tool and our 1.2m Auxiliary Telescope equipped with a subset of identical hardware and software as the Simonyi Telescope. Finally, we will describe our on on-sky testing strategy.
