The FIRST-PL instrument on the Subaru Telescope enables a new observational capability: measuring stellar spin orientations for indirect constraints on exoplanet orbital geometry. We describe the instrument and demonstrate data reduction techniques to measure the spin orientation of Humu (Altair), whose apparent size i...
A. Walk, S. Vievard, O. Guyon et al.· Astronomical Telescopes + In...· 2 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, polarize...
M. Lucas, L. Close, 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
Subaru/SCExAO/CHARIS enables near-infrared integral field spectropolarimetry. Quantitative polarimetry is useful for a variety of science cases, particularly measurements related to dust grain properties in circumstellar disks. This capability requires correcting for polarization effects from the optical path via a Mue...
Thomas McIntosh, Man-Xuan Zhang, Briley L. Lewis et al.· Astronomical Telescopes + In...· 2 citations
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