Revised Group Sunspot Number for 1640, 1652, and 1741

Abstract

Some studies have shown that our knowledge on solar activity in the years 1640, 1652, and 1741 can be improved. In this contribution, we revise the annual group sunspot numbers for these years from original observations. For the years 1640, 1652 and 1741, we have obtained the corrected values 15.2, 1.8, and 27.3, respectively (instead of the original values 15.0, 4.0, and 57.7).

7 pages, 1 figure, 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
• A Simple Method to Check the Reliability of Annual Sunspot Number in the Historical Period 1610-1847

Cited by in corpus (14)

• Revisiting the Sunspot Number
• Reconstruction of the Sunspot Group Number: the Backbone Method
• 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
• Redefining the limit dates for the Maunder Minimum
• Reconstructed sunspot positions in the Maunder Minimum based on the correspondence of Gottfried Kirch
• Sunspot numbers based on historic records in the 1610s - early telescopic observations by Simon Marius and others
• An Optical Atmospheric Phenomenon Observed in 1670 over the City of Astrakhan Was not a Mid-Latitude Aurora
• Solar Angular Momentum Loss Over the Past Several Millennia
• A Note on the Relationship between Sunspot Numbers and Active Days
• Newly found sunspot observations by Peter Becker from Rostock for 1708, 1709, and 1710