EDP Sciences
Free Access
Volume 489, Number 1, October I 2008
Page(s) 429 - 440
Section The Sun
DOI https://doi.org/10.1051/0004-6361:200809959
Published online 17 July 2008

A&A 489, 429-440 (2008)
DOI: 10.1051/0004-6361:200809959

Stokes imaging polarimetry using image restoration at the Swedish 1-m solar telescope

M. J. van Noort1 and L. H. M. Rouppe van der Voort2

1  Institute for Solar Physics of the Royal Swedish Academy of Sciences, AlbaNova University Center, 106 91 Stockholm, Sweden
    e-mail: noort@astro.su.se
2  Institute of Theoretical Astrophysics, University of Oslo, PO Box 1029 Blindern, 0315 Oslo, Norway
    e-mail: rouppe@astro.uio.no

Received 13 April 2008 / Accepted 2 June 2008

Aims. We aim to achieve both high spatial resolution and high polarimetric sensitivity, using an earth-based 1m-class solar telescope, for the study of magnetic fine structure on the surface of the Sun.
Methods. We use a setup with 3 high-speed, low-noise cameras to construct datasets with interleaved polarimetric states, particularly suitable for Multi-Object Multi-Frame Blind Deconvolution image restorations. We discuss the polarimetric calibration routine and various potential sources of error in the results.
Results. We obtained near diffraction limited images, which have a noise level of $\approx 10^{-3} I_{\rm cont}$. We confirm that dark cores have a weaker magnetic field and a lower inclination angle with respect to the solar surface than the edges of the penumbral filament. We demonstrate that the magnetic field strength in faculae-striations is significantly lower than in other nearby parts of the faculae.

Key words: methods: observational -- techniques: image processing -- techniques: polarimetric -- Sun: magnetic fields -- sunspots -- Sun: faculae, plages

© ESO 2008