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  1. Schmidt, Dirk ; Schreiber, Laura ; Vernet, Elise (Ed.)
    The MMT Adaptive optics exoPlanet characterization System (MAPS) is an exoplanet characterization program that encompasses instrument development, observational science, and education. The instrument we are developing for the 6.5m MMT observatory is multi-faceted, including a refurbished 336-actuator adaptive secondary mirror (ASM); two pyramid wavefront sensors (PyWFS's); a 1-kHz adaptive optics (AO) control loop; a high-resolution and long-wavelength upgrade to the Arizona infraRed Imager and Echelle Spectrograph (ARIES); and a new-AO-optimized upgrade to the MMT-sensitive polarimeter (MMT-Pol). With the completed MAPS instrument, we will execute a 60-night science program to characterize the atmospheric composition and dynamics of ~50-100 planets around other stars. The project is approaching first light, anticipated for Summer/Fall of 2022. With the electrical and optical tests complete and passing the review milestone for the ASM's development, it is currently being tuned. The PyWFS's are being built and integrated in their respective labs: the visible-light PyWFS at the University of Arizona (UA), and the infrared PyWFS at the University of Toronto (UT). The top-level AO control software is being developed at UA, with an on-sky calibration algorithm being developed at UT. ARIES development continues at UA, and MMT-Pol development is at the University of Minnesota. The science and education programs are in planning and preparation. We will present the design and development of the entire MAPS instrument and project, including an overview of lab results and next steps. 
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  2. Schmidt, Dirk ; Schreiber, Laura ; Vernet, Elise (Ed.)
    The MMTO Adaptive optics exoPlanet characterization System (MAPS) is an ongoing upgrade to the 6.5-meter MMT Observatory on Mount Hopkins in Arizona. MAPS includes an upgraded adaptive secondary mirror (ASM), upgrades to the ARIES spectrograph, and a new AO system containing both an optical and near-infrared (NIR; 0.9-1.8 μm) pyramid wavefront sensor (PyWFS). The NIR PyWFS will utilize an IR-optimized double pyramid coupled with a SAPHIRA detector: a low-read noise electron Avalanche Photodiode (eAPD) array. This NIR PyWFS will improve MAPS's sky coverage by an order of magnitude by allowing redder guide stars (e.g. K & M-dwarfs or highly obscured stars in the Galactic plane) to be used. To date, the custom designed cryogenic SAPHIRA camera has been fully characterized and can reach sub-electron read noise at high avalanche gain. In order to test the performance of the camera in a closed-loop environment prior to delivery to the observatory, an AO testbed was designed and constructed. In addition to testing the SAPHIRA's performance, the testbed will be used to test and further develop the proposed on-sky calibration procedure for MMTO's ASM. We will report on the anticipated performance improvements from our NIR PyWFS, the SAPHIRA's closed-loop performance on our testbed, and the status of our ASM calibration procedure. 
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  3. Schmidt, Dirk ; Schreiber, Laura ; Vernet, Elise (Ed.)
    The MMT Adaptive optics exoPlanet characterization System (MAPS) is a broad overhaul and upgrade of AO instrumentation at the 6.5-m MMT observatory, from deformable secondary mirror, through pyramid wavefront sensors in both the visible and near-infrared, to improved science cameras. MAPS is an NSF MSIP-funded program whose ultimate goal is a facility optimized for exoplanet characterization. Here we describe the laboratory testing and calibration of one MAPS component: the refurbished MMT adaptive secondary mirror (ASM). The new ASM includes a complete redesign of electronics and actuators, including simplified hub-level electronics and digital electronics incorporated into the actuators themselves. The redesign reduces total power to <~300W, from the original system's 1800W, which in turn allows us to eliminate liquid cooling at the hub with no loss of performance. We present testing strategies, results, and lessons learned from laboratory experience with the MAPS ASM. We discuss calibrations first on the level of individual actuators, including capacitive position sensing, force response function, and individual closed-loop position control with an improved control law. We then describe investigations into the full ASM system - hub, actuators, thin shell, and human - to understand how to optimize interactions between components for dynamical shape control using a feedforward matrix. Finally, we present our results in the form of feedforward matrix and control law parameters that successfully produce a desired mirror surface within 1ms settling time. 
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  4. Schmidt, Dirk ; Schreiber, Laura ; Vernet, Elise (Ed.)
    We are upgrading and refurbishing the first-generation adaptive-secondary mirror (ASM)-based AO system on the 6.5-m MMT in Arizona, in an NSF MSIP-funded program that will create a unique facility specialized for exoplanet characterization. This update includes a third-generation ASM with embedded electronics for low power consumption, two pyramid wavefront sensors (optical and near-IR), and an upgraded ARIES science camera for high-resolution spectroscopy (HRS) from 1-5 μm and MMT-POL science camera for sensitive polarization mapping. Digital electronics have been incorporated into each of the 336 actuators, simplifying hub-level electronics and reducing the total power to 300 W, down from 1800 W in the legacy system — reducing cooling requirements from active coolant to passive ambient cooling. An improved internal control law allows for electronic damping and a faster response. The dual pyramid wavefront sensors allow for a choice between optical or IR wavefront sensing depending on guide star magnitude, color, and extinction. The HRS upgrade to ARIES enables crosscorrelation of molecular templates to extract atmospheric parameters of exoplanets. The combination of these upgrades creates a workhorse instrument for exoplanet characterization via AO and HRS to separate planets from their host stars, with broad wavelength coverage and polarization to probe a range of molecular species in exoplanet atmospheres. 
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  5. Schmidt, Dirk ; Schreiber, Laura ; Vernet, Elise (Ed.)
    MAPS, MMT Adaptive optics exoPlanet characterization System, is the upgrade of the adaptive optics system for 6.5-m MMT. It is an NSF MSIP-funded project that includes developing an adaptive-secondary mirror, visible and near-infrared pyramid wavefront sensors, and the upgrade of Arizona infrared imager and echelle spectrograph (ARIES) and MMT High Precision Imaging Polarimeter (MMTPol) science cameras. This paper will present the design and development of the visible pyramid wavefront sensor, VPWFS. It consists of an acquisition camera, a fast-steering tip-tilt modulation mirror, a pyramid, a pupil imaging triplet lens, and a low noise and high-speed frame rate based CCID75 camera. We will report on hardware and software, present the laboratory characterization results of individual subsystems, and outline the on-sky commissioning plan. 
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