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Proceedings Paper

Diffraction-limited spectropolarimeter: Phase I
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Paper Abstract

A diffraction limited spectro-polarimeter is under construction at the National Solar Observatory in collaboration with the High Altitude Observatory. The scientific objective of the project is to measure the magnetic fields on the Sun up to the diffraction limit of the Dunn Solar Telescope. The same instrument would also measure the magnetic field of large sunspots or sunspot groups with reasonable spatial resolution. This requires a flexible image scale which cannot be obtained with the current Advanced Stokes Polarimeter (ASP) without loosing 50% of the light. The new spectro-polarimeter is designed in such a way that the image scale can be changed without loosing much light. It can work either in high-spatial resolution mode (0.09 arcsec per pixel) with a small field of view (FOV: 65 arcsec) or in large FOV mode (163 arcsec) with low-spatial resolution (0.25 arcsec per pixel). The phase-I of this project is to design and build the spectrograph with flexible image scale. Using the existing modulation, calibration optics of the ASP and the ASP control and data acquisition system with ASP-CHILL camera, the spectrograph was tested for its performance. This paper will concentrate on the performance of the spectrograph and will discuss some preliminary results obtained with the test runs.

Paper Details

Date Published: 14 February 2003
PDF: 11 pages
Proc. SPIE 4843, Polarimetry in Astronomy, (14 February 2003); doi: 10.1117/12.459281
Show Author Affiliations
Kasiviswanathan Sankarasubramanian, National Solar Observatory (United States)
David F. Elmore, National Ctr. for Atmospheric Research (United States)
Bruce W. Lites, National Ctr. for Atmospheric Research (United States)
Michael Sigwarth, Kiepenheuer-Institut fuer Sonnenphysik (United States)
Thomas R. Rimmele, National Solar Observatory (United States)
Steven L. Hegwer, National Solar Observatory (United States)
Scott Gregory, National Solar Observatory (United States)
Kim V. Streander, National Ctr. for Atmospheric Research (United States)
Lawrence M. Wilkins, National Solar Observatory (United States)
K. Richards, National Solar Observatory (United States)
C. Berst, National Solar Observatory (United States)


Published in SPIE Proceedings Vol. 4843:
Polarimetry in Astronomy
Silvano Fineschi, Editor(s)

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