The Butterfly Diagram in the Eighteenth Century
- 131 Downloads
Digitized images of the drawings by J.C. Staudacher were used to determine sunspot positions for the period 1749 – 1796. From the entire set of drawings, 6285 sunspot positions were obtained for a total of 999 days. Various methods have been applied to find the orientation of the solar disk, which is not given for the vast majority of the drawings by Staudacher. Heliographic latitudes and longitudes in the Carrington rotation frame were determined. The resulting butterfly diagram shows a highly-populated Equator during the first two cycles (cycles 0 and 1 in the usual counting since 1749). An intermediate period is cycle 2, whereas cycles 3 and 4 show a typical butterfly shape. A tentative explanation may be the transient dominance of a quadrupolar magnetic field during the first two cycles.
KeywordsSun: sunspots Sun: magnetic field
Unable to display preview. Download preview PDF.
- Küker, M., Arlt, R., Rüdiger, G.: 1999, The Maunder minimum as due to magnetic Λ-quenching. Astron. Astrophys. 343, 977 – 982. Google Scholar
- Meeus, J.: 1985, Astronomical Formulae for Calculators, 3rd edn., Willmann-Bell, Richmond. Google Scholar
- Tobias, S.M.: 1997, The solar cycle: parity interactions and amplitude modulation. Astron. Astrophys. 322, 1007 – 1017. Google Scholar
- Wolf, R.: 1857, Mittheilungen üer die Sonnenflecken. Vierteljahressch. Naturforsch. Ges. Zürich 2, 272 – 299. Google Scholar