| | 27 | || '''28.09.2018[[BR]](11hrs, MPIA Hoersaal)''' || '''Prashant Pathak (ESO)''' || '''Closed-loop correction of atmospheric dispersion for high-contrast coronography and astrometry'''[[BR]][[BR]]On ground-based telescopes employing adaptive optics (AO) systems, atmospheric dispersion compensation is essential to deliver high-quality imaging, and critical for coronagraphy and high-precision astrometry. Imperfect compensation by an atmospheric dispersion compensator (ADC) can be addressed with a high-precision on-sky measurement of residual dispersion in a closed-loop control scheme. [[BR]][[BR]]In this talk, Prashant Pathak will present a focal plane based technique, which utilizes the chromatic scaling of speckles to measure residual dispersion (atmospheric and optical) in the final science image. The residual dispersion can be accurately measured and subsequently corrected in a closed-loop control. On-sky residual dispersion of < 1 mas across H-band was demonstrated, which reduced from 8.4 mas before closing the loop.[[BR]][[BR]]Presentation: English[[BR]][https://svn.mpia.de/trac/gulli/att/raw-attachment/wiki/AlteVortraege2018S2/2018-09-28_HCI_ESO.pdf Slides: English][[BR]]Questions: German, English || |
