Achieving smooth and efficient slew movements on telescope mounts is crucial for minimizing structural stress, reaching maximum velocities, and ensuring efficient operation. Traditional slew trajectory generation methods often fall short in optimizing trajectories for time, resulting in unnecessarily long slew times that reduce telescope efficiency and potentially affect observation opportunities. Additionally, traditional methods often fail to converge smoothly to tracking velocities, leading to abrupt changes in motion that can compromise settling time. This paper presents a novel time-optimal jerk-limited trajectory generator algorithm for slew movements and its current implementation at the SOAR telescope as part of the Mount Control Upgrade Project. This algorithm effectively addresses these limitations by simultaneously optimizing for user-defined constraints on position, velocity, acceleration, and jerk while achieving minimum time. The algorithm produces a jerk-constrained trajectory that converges to a constant velocity reference specified by position, velocity, and time (PVT) commands, ensuring smooth and efficient convergence to tracking velocities while minimizing structural stress and settling time. The proposed algorithm is simple to implement and can be used to generate smooth slew trajectories in telescopes and actuators in general.
Modern Skipper CCD technology has been used in particle physics experiments since its first successful demonstration in 2017. This technology has been demonstrated to achieve extremely low readout noise (0.039 e-rms/pix), while maintaining the benefits of conventional CCD detectors. The extremely low noise of Skipper CCDs presents a very interesting potential for certain astronomical applications where photon shot noise does not dominate, and the ability of Skipper CCDs to be tuned for a desired readout noise allows for a wide range of applications. In the current paper, we focus on the engineering work performed in cryo-mechanics and electronics (Dewar, detector mount, preamplifier, etc.) at NOIRLab-CTIO in order to perform on-sky testing of a mosaic of 4 Skipper CCDs using the SOAR Integral Field Spectrograph (SIFS). This work was performed in the context of a NOIRLab/LNA/Fermilab/U.Chicago/LBNL collaboration for testing Skipper devices for astronomy. We also present the mosaic characterization results of the detectors from the laboratory, as well as the final engineering performance results from on sky observations.
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