Sign on

SAO/NASA ADS Astronomy Abstract Service

· Find Similar Abstracts (with default settings below)
· Full Refereed Journal Article (PDF/Postscript)
· Full Refereed Scanned Article (GIF)
· References in the article
· Citations to the Article (12) (Citation History)
· Refereed Citations to the Article
· Also-Read Articles (Reads History)
· Translate This Page
New information on solar activity, 1779-1818, from Sir William Herschel's unpublished notebooks
Hoyt, Douglas V.; Schatten, Kenneth H.
AA(Research and Data Systems Corp., Greenbelt, MD), AB(NASA, Goddard Space Flight Center, Greenbelt, MD)
Astrophysical Journal, Part 1 (ISSN 0004-637X), vol. 384, Jan. 1, 1992, p. 361-384. (ApJ Homepage)
Publication Date:
Solar Physics
NASA/STI Keywords:
Solar Activity, Sunspots, Astronomical Observatories, Solar Cycles
Bibliographic Code:


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.

Printing Options

Print whole paper
Print Page(s) through

Return 600 dpi PDF to Acrobat/Browser. Different resolutions (200 or 600 dpi), formats (Postscript, PDF, etc), page sizes (US Letter, European A4, etc), and compression (gzip,compress,none) can be set through the Printing Preferences

More Article Retrieval Options

HELP for Article Retrieval

Bibtex entry for this abstract   Preferred format for this abstract (see Preferences)


Find Similar Abstracts:

Use: Authors
Keywords (in text query field)
Abstract Text
Return: Query Results Return    items starting with number
Query Form
Database: Astronomy
arXiv e-prints