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Paper: ATST Telescope Calibration: Summary of Studies and their Conclusions
Volume: 463, 2nd ATST-EAST Workshop in Solar Physics: Magnetic Fields from the Photosphere to the Corona
Page: 307
Authors: Elmore, D. F.
Abstract: The ATST Polarimetry Working Group (PWG) has concluded that ATST telescope calibration will be performed using solar data themselves. Two studies prepared for the PWG contributing to that conclusion are presented. The first study utilizes a model of 630 nm Stokes profiles generated in solar active network as input to a polarization model of the ATST primary and secondary mirrors. Correlations among polarization parameters seen in the resulting line profiles are used to infer properties of the mirrors and compared to those values used to create the model telescope. In this closed exercise, the inversion method was tuned to best recover ATST mirror properties. The second of these studies applies this correlation method to calibrated solar observations from the Dunn Solar Telescope (Sacramento Peak, NM USA) over the course of a day recorded by the Facility Infrared Spectro-polarimeter at 630 nm to infer the polarization properties of the telescope entrance window, turret mirrors, and exit window. The fidelity of the fit to the inferred parameters when scaled to the polarization levels of ATST indicates the applicability of this technique to that new telescope.
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