Socas-Navarro, H.; Elmore, D.; Asensio-Ramos, A.; Harrington, D. M.
Referencia bibliográfica
Astronomy and Astrophysics, Volume 531, id.A2
Fecha de publicación:
7
2011
Revista
Número de citas
29
Número de citas referidas
23
Descripción
Accurate astrophysical polarimetry requires a proper characterization of
the polarization properties of the telescope and instrumentation
employed to obtain the observations. Determining the telescope and
instrument Muller matrix is becoming increasingly difficult with the
increase in aperture size, precision requirements and instrument
complexity of new and upcoming projects. We have carried out a detailed
multi-wavelength characterization of the Dunn Solar Telescope (DST) at
the National Solar Observatory/Sacramento Peak as a case study and
explore various possibilites for the determination of its polarimetric
properties. We show that the telescope model proposed in this paper is
more suitable than that in previous work in that it describes better the
wavelength dependence of aluminum-coated mirrors. We explore the
adequacy of the degrees of freedom allowed by the model using a novel
mathematical formalism. Finally, we investigate the use of polarimeter
calibration data taken at different times of the day to characterize the
telescope and find that very valuable information on the telescope
properties can be obtained in this manner. The results are also
consistent with the entrance window polarizer measurements. This general
method opens interesting possibilities for the calibration of future
large-aperture telescopes and precision polarimetric instrumentation.
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