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 details: | Andrea DierckeORCiDGND, Rainer ArltGND, Carsten DenkerORCiDGND |
|---|---|
| URN: | urn:nbn:de:kobv:517-opus4-413922 |
| DOI: | https://doi.org/10.25932/publishup-41392 |
| ISSN: | 1866-8372 |
| Title of parent work (English): | Postprints der Universität Potsdam : Mathematisch Naturwissenschaftliche Reihe |
| Publication series (Volume number): | Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe (577) |
| Publication type: | Postprint |
| Language: | English |
| Date of first publication: | 2019/02/06 |
| Publication year: | 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 |
| Issue: | 577 |
| Number of pages: | 2 |
| 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 |
| DDC classification: | 5 Naturwissenschaften und Mathematik / 52 Astronomie / 520 Astronomie und zugeordnete Wissenschaften |
| Peer review: | Referiert |
| Publishing method: | Open Access |
| Grantor: | Cambridge University Press (CUP) |
| License (German): |  Keine öffentliche Lizenz: Unter Urheberrechtsschutz |
