Advancing adaptive secondary mirrors for astronomy

Adaptive secondary mirrors (ASMs) on telescopes correct the blurring from the Earth's atmosphere in real time. They flex thousands of times a second to sharpen images and capture more light, aiding astronomers to study faint, distant objects in space. Innovative design coupled with advanced manufacturing and testing processes now cut the costs of deploying ASMs, making the technology practical for telescopes of every size. ASMs also improve the image quality on older telescopes that suffer from, e.g., warped supports or optical misalignment. Fixing these can cut observation time by half, delivering more science per hour of telescope time. This project installs two ASMs – one each at the NASA Infrared Telescope Facility and the University of Hawaii's 2.2-meter telescope – and builds automated controls that let a telescope correct its own image quality, a step toward smart, self-optimizing observatories. The project also trains early-career scientists and undergraduate students in Hawaii, an NSF-designated EPSCoR state. This project advances hybrid-variable reluctance (HVR) actuator ASMs, extending them for use on small-, medium-, and large-aperture ground-based telescopes. On-sky performance has been demonstrated at NASA IRTF. Wavefront sensing and control systems needed to bring the IRTF and UH 2.2-meter ASMs into regular science operations at the diffraction limit will be completed. The project further develops control architectures, calibration methods and lab testing procedures across telescope scales, including lower actuator-count systems for smaller apertures. ASM correction of ground-layer and static aberrations is especially valuable on older, small telescopes where such aberrations are common. This offers a path to a cost-effective upgrade of twenty-five 1-2 meter and fourteen 2-4 meter US-affiliated telescopes. The project also lays the groundwork for autonomous, self-optimizing "smart telescopes" that adjust image quality to science objectives in real time. This complements the growing role of robotic, rapid-follow-up observing, and in so doing this project trains a workforce for this technology development. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.