Abstract
This paper discusses some aspects of the zero-level problem of solar magnetographs which is particularly important for observations of large-scale magnetic fields on the Sun. Experiments at the STOP telescope of the Sayan Solar Observatory (SSO) showed that in addition to the adjustment errors of the polarization analyzer, the focusing errors of the spectrograph, and the linear polarization of the light (these mechanisms were known previously [5]), “spurious” signals of the magnetograph are brought about by polarization effects in the optical details preceding the polarization analyzer (coelostat mirrors and the objective) and aberration errors of the spectrograph. Disadvantages of the method of monitoring the zero level from the nonmagnetic line λ 512.37 nm FeI are pointed out. A correlation was made between the observations of the solar mean magnetic field in the SSO and WSO (Wilcox Solar Observatory, Stanford, USA) — the observatories which use the different methods of zero-level monitoring.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
P. H. Scherrer, “A Study of the Mean Solar Magnetic Field,” Ph.D. Dissertation, SUIPR Report No. 554 (1973).
R. Howard, J. E. Boyden, D. H. Brunning, M. K. Clark, H. W. Crist, and B. J. LaBonte,Sol. Phys.,87, 195 (1983).
A. Severny,Nature,224, 53 (1969).
P. H. Scherrer, J. M. Wilcox, L. Svalgaard, T. L. Duvall, P. H. Dittmer, and E. K. Gustafson,Sol. Phys.,54, 353 (1977).
T. L. Duvall, “A Study of Large-Scale Solar Magnetic and Velocity Fields,” Ph.D. Dissertation, SUIPR Report No. 724 (1977).
V. M. Grigoryev and M. L. Demidov,Sol. Phys.,114, 147 (1987).
M. L. Demidov,Kinem. Fiz. Neb. Tel,7, No. 6, 62 (1991).
V. I. Skomorovsky,Issled. Geomagn. Aéronom. Fiz. Sol., No. 95, 97 (1991).
N. N. Mikhel'son,Optical Telescopes: Theory and Design [in Russian], Nauka, Moscow (1976).
H. Balthasar,Astron. Astrophys. Suppl. Ser.,72, 473 (1988).
V. A. Kotov and A. B. Severny,The Mean Magnetic Field of the Sun as a Star. Catalogue of 1968–1976 [in Russian], B.-M. International Center (1983).
D. L. Mickey,Sol. Phys.,97, 223 (1985).
G. Bernet,JOSO Annual Report (1979), p. 147.
M. Owner-Petersen, “On the Polarization Effects of Stress-Induced Birefringence in the Entrance Window of Solar Telescopes,” LEST Foundation Technical Report No. 49 (1991);Nature,326, 270 (1987).
J. Sanchez Almeida and V. Martinez Pillet,Astron. Astrophys.,260, 543 (1992).
J. O. Stenflo,Solar Magnetic Fields. Polarized Radiation Diagnostics, Kluwer Academic Publishers (1994).
Author information
Authors and Affiliations
Additional information
Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 39, No. 10, pp. 1306–1314, October, 1996.
In closing, the author wishes to express his gratitude to V. M. Grigoryeva and V. A. Kotov (the Crimean Observatory) for discussing some problems in this study, S. Chuprakov (Institute of Solar-Terrestrial Physics, Siberian Branch of the RAS) for consultations on how to operate the DEMOS software, and P. Scherrer (SSO) for providing original Stanford observations of the solar MMF and allowing us to use them in this paper.
The results presented in this paper were supported in part by the International Science Foundation under Grant No. NN3000 and the Russian Foundation for Fundamental Research under Grant No. 96-02-16638.
Rights and permissions
About this article
Cite this article
Demidov, M.L. Zero-level problem of solar magnetographs and observations of large-scale magnetic fields. Radiophys Quantum Electron 39, 874–879 (1996). https://doi.org/10.1007/BF02120978
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF02120978