Closed-loop atmospheric dispersion correction for high-contrast imaging with MagAO-X
Abstract
Incoming starlight is refracted as it enters Earth’s atmosphere from the vacuum of space. The wavelength dependence of atmospheric refraction causes elongation of the broadband PSF of ground-based telescopes, especially in the visible spectrum. The result is degraded image quality alongside reduced coronagraph light-blocking efficiency, both of which limit high-contrast observations. An atmospheric dispersion corrector (ADC) is a dispersive optic used to compensate for this effect. Current methods for dispersion compensation use analytical models to anticipate dispersion strength based on parameters such as site altitude and telescope zenith angle; however, dispersion strength is also dictated by a number of factors that cannot be measured, including instantaneous humidity, temperature, and pressure along the line of sight to the star. This leads to constant over- or under correction of the true atmospheric dispersion by the ADC. In this work, we use the Magellan extreme adaptive optics system MagAO-X at Las Campanas Observatory to measure and correct residual atmospheric dispersion in real-time. The amount of residual dispersion is encoded in the orientation of satellite spots generated by using MagAO-X’s deformable mirror as a diffraction grating. We have used these real-time measurements as feedback for closed-loop control of the ADCs on-sky at visible and NIR wavelengths, reducing residual atmospheric dispersion down to sub-mas/µm levels. Active atmospheric dispersion correction on MagAO-X is a precursor to high-contrast imaging with Extreme AO for the upcoming Extremely Large Telescopes, where high-precision dispersion compensation will be required to image exoplanets in reflected light.
Authors 20
-
Affiliation as printed
Wyant College of Optical Sciences, The Univ. of Arizona (United States)
-
Leiden University · University of Arizona · Leiden Observatory
Affiliation as printed
Leiden Observatory, Leiden Univ. (Netherlands)
Steward Observatory, The Univ. of Arizona (United States)
-
Affiliation as printed
Steward Observatory, The Univ. of Arizona (United States)
-
Affiliation as printed
Steward Observatory, The Univ. of Arizona (United States)
-
University of Arizona · National Astronomical Observatory of Japan
Affiliation as printed
Steward Observatory, The Univ. of Arizona (United States)
Subaru Telescope, National Observatory of Japan (United States)
Wyant College of Optical Sciences, The Univ. of Arizona (United States)
-
Affiliation as printed
Steward Observatory, The Univ. of Arizona (United States)
-
Northrop Grumman (United States)
Affiliation as printed
Northrop Grumman Corp. (United States)
-
Affiliation as printed
Steward Observatory, The Univ. of Arizona (United States)
-
Affiliation as printed
Wyant College of Optical Sciences, The Univ. of Arizona (United States)
-
Affiliation as printed
Wyant College of Optical Sciences, The Univ. of Arizona (United States)
-
Affiliation as printed
Wyant College of Optical Sciences, The Univ. of Arizona (United States)
-
University of Arizona · National Astronomical Observatory of Japan
Affiliation as printed
Steward Observatory, The Univ. of Arizona (United States)
Subaru Telescope, National Observatory of Japan (United States)
-
Affiliation as printed
Draper Lab. (United States)
-
Leiden University · Leiden Observatory
Affiliation as printed
Leiden Observatory, Leiden Univ. (Netherlands)
-
Affiliation as printed
Wyant College of Optical Sciences, The Univ. of Arizona (United States)
-
Affiliation as printed
Steward Observatory, The Univ. of Arizona (United States)
-
Affiliation as printed
Flatiron Institute (United States)
-
Affiliation as printed
Wyant College of Optical Sciences, The Univ. of Arizona (United States)
-
Affiliation as printed
Starfire Optical Range (United States)
-
Leiden University · Leiden Observatory
Affiliation as printed
Leiden Observatory, Leiden Univ. (Netherlands)
Cited by 0 stored of 0
No patents citing this paper on Lens.org (checked 2026-10-11).