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Digitization of Spörer’s sunspot drawings

  • Much of our knowledge about the solar dynamo is based on sunspot observations. It is thus desirable to extend the set of positional and morphological data of sunspots into the past. Gustav Spörer observed in Germany from Anklam (1861–1873) and Potsdam (1874–1894). He left detailed prints of sunspot groups, which we digitized and processed to mitigate artifacts left in the print by the passage of time. After careful geometrical correction, the sunspot data are now available as synoptic charts for almost 450 solar rotation periods. Individual sunspot positions can thus be precisely determined and spot areas can be accurately measured using morphological image processing techniques. These methods also allow us to determine tilt angles of active regions (Joy’s law) and to assess the complexity of an active region.

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Author:Andrea DierckeORCiD, Rainer ArltGND, Carsten DenkerORCiD
Parent Title (English):Postprints der Universität Potsdam : Mathematisch Naturwissenschaftliche Reihe
Series (Serial Number):Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe (577)
Document Type:Postprint
Date of first Publication:2019/02/06
Year of Completion:2012
Publishing Institution:Universität Potsdam
Release Date:2019/02/06
Tag:astronomical databases: miscellaneous; history and philosophy of astronomy; sun: activity; sun: photosphere; sun: sunspots; techniques: image processing
First Page:63
Last Page:64
Source:Proceedings of the International Astronomical Union 8 (2012) Symposium 294 pp. 63–64 DOI 10.1017/S1743921313002214
Organizational units:Mathematisch-Naturwissenschaftliche Fakultät
Dewey Decimal Classification:5 Naturwissenschaften und Mathematik / 52 Astronomie / 520 Astronomie und zugeordnete Wissenschaften
Peer Review:Referiert
Publication Way:Open Access
Grantor:Cambridge University Press (CUP)
Licence (German):License LogoKeine Nutzungslizenz vergeben - es gilt das deutsche Urheberrecht