Direct spectroscopy is a very promising approach to characterizing the atmospheres of nearby rocky exoplanets, but non-common path aberrations (NCPA), which are differential aberrations between the science optical path and the adaptive optics optical path, can leak through the coronagraph and create speckles that mimic...
S. Haffert, J. Liberman, J. Males et al.· Astronomy & Astrophysics· 0 citations
Current high-contrast imaging instruments are limited by wavefront errors originating from non-common path aberrations (NCPAs) due, for example, to manufacturing errors in the optics and temperature drifts in the system. These create quasi-static speckles in the final science image that are difficult to distinguish fro...
E. Tonucci, S. Haffert, J. Males et al.· Astronomical Telescopes + In...· 1 citation
MagAO-X is a visible-light extreme adaptive optics instrument on the 6.5 meter Magellan Clay Telescope, recently upgraded to enable high-contrast polarimetric differential imaging (PDI) in r', i', and z' filters. Polarimetry is a powerful technique for suppressing unpolarized starlight and isolating the faint, polarize...
M. Lucas, L. Close, J. Males et al.· Astronomical Telescopes + In...· 2 citations
Laser guide star (LGS) adaptive optics has become widespread in ground-based astronomy. It is also the most promising approach for countering atmospheric distortions in uplink optical satellite communications and laser-based space debris tracking and maneuvering. The best performance is achieved when the LGS is created...
Konstantin B. Holzner, Christopher Renkl, M. Brekenfeld et al.· Astronomical Telescopes + In...· 2 citations
The next generation of Extremely Large Telescopes (ELTs) and the Habitable Worlds Observatory (HWO) require active speckle suppression to directly image exo-Earths. Focal plane wavefront sensing and control allows us to detect and remove time-varying speckles through measurements of the electric field, ideally with a s...
J. Liberman, S. Haffert, J. Males et al.· Astronomical Telescopes + In...· 2 citations
A lingering technical challenge for pyramid wavefront sensors (PyWFS) is their change in response between calibration and correction residuals, a quantity known as optical gain (OG). Given the prevalent use of PyWFSs in current and planned high contrast adaptive optics (AO), understanding and reliably measuring OG for...
E. McEwen, J. Males, O. Guyon et al.· Astronomical Telescopes + In...· 1 citation
Direct imaging of exoplanets is very tricky and requires extremely well corrected wavefronts. Especially low order modes are detrimental to the performance of coronagraphs at their inner-working angle. However, that is precisely where conventional AO systems have the highest residuals that are caused by servo-lag error...
S. Haffert, J. Males, P. Johnson et al.· Astronomical Telescopes + In...· 0 citations
MagAO-X is a visible-light extreme adaptive optics instrument on the 6.5 meter Magellan Clay Telescope, recently upgraded to enable high-contrast polarimetric differential imaging (PDI) in r', i', and z'filters. Polarimetry is a powerful technique for suppressing unpolarized starlight and isolating the faint, polarized...
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-bl...
K. Twitchell, S. Haffert, J. Males et al.· Astronomical Telescopes + In...· 4 citations
By combining a physical optics model with a flexible machine learning model, this work can avoid introducing unphysical features in the resulting PSF estimate and explores the temporal coherence of structures in telemetry and the limitations of learning this relationship from data sampled on such different timescales.
Joseph D. Long, S. Haffert, J. Males et al.· Astronomical Telescopes + In...· 1 citation
One of the main limitations of ground-based extreme adaptive optics systems (XAO) is the balance between the temporal and photon noise error. The unmodulated Pyramid Wavefront Sensor (uPWFS) promises significant gains in sensitivity over its modulated counterpart, but its practical use is limited by its linearity range...
R. Landman, Liam Koning, S. Haffert et al.· Astronomical Telescopes + In...· 1 citation
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