A new adaptive secondary mirror for astronomy

University Of Hawaii, Honolulu

Investigators

Abstract

Adaptive optics (AO) removes aberrations in starlight caused by the turbulent atmosphere. It greatly enhances astronomical observations from ground-based telescopes. This project will develop a more capable and reliable AO system than currently exists. The main technical advance will be an innovative adaptive secondary mirror. This optical element combines a part of the telescope with a part of the AO system. It simplifies the optics and improves performance. This project will have a broad impact on major ground-based observatories. It will reduce the complexity and improve the reliability of AO, which is essential for these observatories. The project will also support both undergraduate and graduate students, and it will engage high school students as summer interns. An AO system with its correcting element integrated into the telescope optics is an ideal implementation since it simplifies the optics, maximizes the system sensitivity, and provides both narrow-field high-resolution and wide-field modest resolution observations free of the optical blurring from the atmosphere. This enables unique science at very high angular resolution at infrared wavelengths and roughly doubles the survey efficiency of wide-field observations. However, current adaptive secondary mirrors are expensive, complex, and suffer from a range of failure modes. These limitations arise from the choice of the type of actuator and are not fundamental. This project will deploy an adaptive secondary mirror on the University of Hawaii 2.2-meter telescope based on a new actuator technology developed by collaborators at The Netherlands Organization for Applied Research (TNO). The new actuator has a linear displacement with input command, produces a higher force actuation, and is more efficient than the voice-coil actuators used in current systems. This will result in a simpler, more capable, and more reliable adaptive secondary mirror. This work is critical for the next generation extremely large telescopes where an adaptive secondary mirror will need to be very reliable. In addition, by reducing cost, this project can bring adaptive secondaries within the reach of smaller aperture telescopes. 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.