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New information on solar activity, 1779-1818, from Sir William Herschel's unpublished notebooks
- Source :
- Astrophysical Journal, Part 1. 384
- Publication Year :
- 1992
- Publisher :
- United States: NASA Center for Aerospace Information (CASI), 1992.
-
Abstract
- Herschel's observations are analyzed in order to determine the level of solar activity for solar cycle 5. It is concluded that solar cycle 5 may have peaked as early as 1801 based upon the average number of groups with a probable secondary maximum in 1804. Depending on the technique adopted, the peak for solar cycle 5 occurred sometime between 1801 and 1804, rather than 1805.2, as commonly assumed. Instead of a solar cycle of 17 yrs, a cycle length of 14 yrs is found. It is also found that the peak yearly mean sunspot number is only about 38 rather than 45, as deduced by Wolf (1855). A technique for making early solar observations homogeneous with modern sunspot observations is proposed.
- Subjects :
- Solar Physics
Subjects
Details
- Language :
- English
- ISSN :
- 0004637X
- Volume :
- 384
- Database :
- NASA Technical Reports
- Journal :
- Astrophysical Journal, Part 1
- Publication Type :
- Report
- Accession number :
- edsnas.19920036711
- Document Type :
- Report
- Full Text :
- https://doi.org/10.1086/170879