Progress report on the integration of the IRTF adaptive secondary mirror

Ellen Lee; Mark Chun; Ruihan Zhang; Olivier Lai; Michael Connelley; Tony Denault; Jacob Taylor; John Rayner; Max Baeten; Arjo Bos; Matias Kidron; Fred Kamphues; Stefan Kuiper; Wouter Jonker; Alan Ryan; Philip Hinz

arXiv · 2607.04385

Progress report on the integration of the IRTF adaptive secondary mirror

Ellen Lee·Mark Chun·Ruihan Zhang·Olivier Lai·Michael Connelley·Tony Denault·Jacob Taylor·John Rayner·Max Baeten·Arjo Bos·Matias Kidron·Fred Kamphues·Stefan Kuiper·Wouter Jonker·Alan Ryan·Philip Hinz

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Abstract

IRTF-ASM-1 is the first on-sky adaptive secondary mirror using the hybrid variable reluctance (HVR) actuators developed by the Netherlands Organization for Applied Scientific Research (TNO). Since its first light in April 2024, the ASM has continued to work consistently well with no hardware issues. The primary purpose of IRTF-ASM-1 is to serve as a demonstration of the HVR actuator technology, both in terms of verifying its robustness and testing calibration methods that are relevant to larger ASMs. However, as the ASM has proven to be easy to handle and reliable in its performance, we are moving toward integrating the ASM for long-term use at IRTF. We present closed loop results with the ASM and IRTF's off-axis facility wavefront sensor FELIX. Correcting the first seven Zernike modes through coma at 90-180 Hz, we are able to enhance the seeing by a factor of 1.8 in FWHM under 0."5 seeing conditions. We also performed the first science observations with the ASM in "static" mode and demonstrated that we can improve the throughput of IRTF's slit spectrograph by approximately a factor of 2, although this requires good reference slopes in FELIX. In the near future, we plan to optimize the calibration of reference slopes in FELIX and streamline the software so that the system can be operated by a non-AO expert.

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Ellen Lee, Mark Chun, Ruihan Zhang, Olivier Lai, Michael Connelley, Tony Denault, Jacob Taylor, John Rayner, Max Baeten, Arjo Bos, Matias Kidron, Fred Kamphues, Stefan Kuiper, Wouter Jonker, Alan Ryan, Philip Hinz. 2026-07-05. Progress report on the integration of the IRTF adaptive secondary mirror. https://arxiv.org/abs/2607.04385

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