Abstract
A high-resolution videomagnetograph that records the images of opposite circular polarization simultaneously has been constructed for the Swedish vacuum solar telescope at La Palma. Magnetograms are obtained by off-line integration of bursts consisting of typically 50 frames of 20 ms exposures, with bad frames rejected, and the frame-to-frame image motion of the remaining frames compensated for by cross-correlation techniques. The short exposures combined with frame selection and elimination of image motion optimizes the resolution and thereby also the S/N, allowing good magnetograms to be obtained with an effective exposure time of less than 1 s at an image scale of 0.1″ pixel−1. The advantages and limitations of the system are discussed and compared with other techniques of making filter magnetograms are discussed.
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References
Ai, G. and Hu, Y.: 1986, Acta Astron. Sinica 27, No. 2, 173.
Capitani, C.: 1988, ‘Analisi della polarizzazione strumentale del telescopio della Torre Solare di Arcetri’, Thesis at Univ. of Firenze, Italy.
Hagyard, M. J., West, E. A., and Cumings, N. P.: 1984, The New MSFC Solar Vectore Magnetograph, NASA TM-82568, MSFC.
Harvey, J., Livingston, W., and Slaughter, C.: 1972, in Line Formation in the Presence of Magnetic Fields, HAO, NCAR, Boulder, Colorado, p. 227.
Jingxiu, W., Zirin, H., and Zhongxian, S.: 1984, The Smallest Observable Elements of Magnetic Flux, BBSO 0234, CalTech.
Lundstedt, H.: 1987, in E.-H. Schröter, M. Vázquez, and A. A. Wyller (eds.), Proc. of the Inaugural Workshop and Round Table Discussion for the D-E-S Telescope Installation on Canary Islands, p. 343.
Lundstedt, H.: 1988, in O. von der Lühe (ed.), High Spatial Resolution Solar Observations, 10th Sacramento Peak Summer Workshop, Sunspot, New Mexico.
November, L. J.: 1986, Appl. Optics 25, 392.
Scharmer, G. B.: 1987, in E.-H. Schröter, M. Vázquez, and A. A. Wyller (eds.), Proc. of the Inaugural Workshop and Round Table Discussion for the D-E-S Telescope Installation on the Canary Islands, p. 349.
Scharmer, G. B.: 1988, in O. von der Lühe (ed.), High Spatial Resolution Solar Observations, 10th Sacramento Peak Summer Workshop, Sunspot, New Mexico.
Scharmer, G. B. and Wang, J.: 1991, Solar Phys. (submitted).
Scharmer, G. B. Brown, D. S., Pettersson, L., and Rehn, J.: 1985, Appl. Optics, 24, No. 16, 2558.
Shi, Z., Wang, J., and Patterson, A.: 1986, The Calibration of Dopplergrams and Magnetograms at BBSO, BBSO No. 0257, CalTech.
Smithson, R. C.: 1973, Solar Phys. 29, 365.
Stenflo, J. O.: 1973, Solar Phys. 32, 41.
Stenflo, J. O.: 1989, Astron. Astrophys. Rev. 1, 3.
Stenflo, J. O. and Harvey J. W.: 1985, Solar Phys. 95, 99.
Stenflo, J. O., Harvey, J. W., Brault, J. W., and Solanki, S.: 1984, Astron. Astrophys. 131, 333.
Tarbell, T., Fergusson, S., Frank, Z., Title, A., and Topka, K.: 1988, in O. von der Lühe (ed.), High Spatial Resolution Solar Observations, 10th Sacramento Peak Summer Workshop, Sunspot, New Mexico.
Tarbell, T., Fergusson, S., Frank, Z., Shine, R., Title, K., Topka, K., and Scharmer, G.: 1990, in J. O. Stenflo (ed.), ‘High Resolution Observations of Emerging Magnetic Fields and Fluxtubes in Quiet and Active Photosphere’, IAU Symp. 138, 147.
Title, A. and Rosenberg, W.: 1981, in R. B. Dunn (ed.), Proc. Sacramento Peak Nat. Obs. Conf., Solar Instrumentation: What's Next, p. 326.
Title, A., Tarbell, T. D., and Topka, KJ. P.: 1977, Astrophys. J. 317, 892.
Unno, W.: 1956, Publ. Astron. Soc. Japan 8, 108.
Von der Lühe, O.: 1983, Astron. Astrophys. 119, 85.
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Lundstedt, H., Johannesson, A., Scharmer, G. et al. Magnetograph observations with the Swedish solar telescope on La Palma. Sol Phys 132, 233–245 (1991). https://doi.org/10.1007/BF00152285
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DOI: https://doi.org/10.1007/BF00152285