A Simple Method to Check the Reliability of Annual Sunspot Number in the Historical Period 1610-1847

Abstract

A simple method to detect inconsistencies in low annual sunspot numbers based on the relationship between these values and the annual number of active days is described. The analysis allowed for the detection of problems in the annual sunspot number series clustered in a few specific periods and unambiguous, namely: i) before Maunder minimum, ii) the year 1652 during the Maunder minimum, iii) the year 1741 in Solar Cycle -1, and iv) the so-called "lost" solar cycle in 1790s and subsequent onset of the Dalton Minimum.

15 pages, 3 figures, to be published in Solar Physics

References in corpus (3)

• Historical Sunspot Observations: A Review
• A solar cycle lost in 1793--1800: Early sunspot observations resolve the old mystery
• The butterfly diagram in the 18th century

Cited by in corpus (13)

• Revisiting the Sunspot Number
• The Maunder minimum (1645--1715) was indeed a Grand minimum: A reassessment of multiple datasets
• A Revised Collection of Sunspot Group Numbers
• A New Calibrated Sunspot Group Series Since 1749: Statistics of Active Day Fractions
• Level and length of cyclic solar activity during the Maunder minimum as deduced from the active day statistics
• Solar cycle indices from the photosphere to the corona: measurements and underlying physics
• Sunspots during the Maunder Minimum from Machina Coelestis by Hevelius
• Sunspot Numbers and Areas from the Madrid Astronomical Observatory (1876-1986)
• Updated sunspot group number reconstruction for 1749-1996 using the active day fraction method
• Revised Group Sunspot Number for 1640, 1652, and 1741
• Sunspot Observations during the Maunder Minimum from the Correspondence of John Flamsteed
• Sunspot numbers based on historic records in the 1610s - early telescopic observations by Simon Marius and others
• A Note on the Relationship between Sunspot Numbers and Active Days