Daniel Mögling's sunspot observations in 1626 - 1629: A manuscript reference for the solar activity before the Maunder Minimum

Abstract

The sunspot groups have been observed since 1610 and their numbers have been used for evaluating the amplitude of solar activity. Daniel Mögling recorded his sunspot observations for more than 100 days in 1626 - 1629 and formed a significant dataset of sunspot records before the Maunder Minimum. Here, we have analysed his original manuscripts in the Universitäts- und Landesbibliothek Darmstadt (ULBD) to review Mögling's personal profile and observational instruments and derive number and positions of the sunspot groups. In his manuscript, we have identified 134 days with an exact sunspot group number and 3 days of additional descriptions. Our analyses have completely revised their observational dates and group number, added 19 days of hitherto overlooked observations, and removed 8 days of misinterpreted observations. We have also revisited sunspot observations of Schickard and Hortensius and revised their data. These results have been compared with the contemporary observations. Moreover, we have derived the sunspot positions from his sunspot drawings and located them at 2°-23° in the heliographic latitude in both solar hemispheres. Contextualised with contemporary observations, these results indicate their temporal migration to lower heliographic latitudes and emphasise its location in the declining phase of Solar Cycle -12 in the 1620s. His observations were probably conducted using a pinhole and camera obscura, which made Mögling likely underestimate the sunspot group number by >~ 33% - 52 %. This underestimation should be noted upon their comparison with the modern datasets.

arXiv comment17 pages, 4 figures, and accepted for publication in the ApJ

References in corpus (25)

• The Solar Cycle
• 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
• Historical Sunspot Observations: A Review
• A Revised Collection of Sunspot Group Numbers
• A New Calibrated Sunspot Group Series Since 1749: Statistics of Active Day Fractions
• Visualization of the challenges and limitations of the long-term sunspot number record
• Sunspot positions and sizes for 1825-1867 from the observations by Samuel Heinrich Schwabe
• New reconstruction of the sunspot group number since 1739 using the direct calibration and "backbone" methods
• Revisited sunspot data: A new scenario for the onset of the Maunder minimum
• Level and length of cyclic solar activity during the Maunder minimum as deduced from the active day statistics
• Sunspot positions, areas, and group tilt angles for 1611-1631 from observations by Christoph Scheiner
• Thaddäus Derfflinger's sunspot observations during 1802-1824: A primary reference to understand the Dalton Minimum
• Updated sunspot group number reconstruction for 1749-1996 using the active day fraction method
• Robustness of Solar-Cycle Empirical Rules Across Different Series Including an Updated ADF Sunspot Group Series
• A Great Space Weather Event in February 1730
• Sunspot characteristics at the onset of the Maunder Minimum based on the observations of Hevelius
• Christian Horrebow's Sunspot Observations -- II. Construction of a Record of Sunspot Positions
• Reanalyses of the Sunspot Observations of Fogelius and Siverus: Two "Long-Term" Observers during the Maunder Minimum
• Number of Sunspot Groups from the Galileo-Scheiner controversy revisited
• Equivalence relations between the Cortie and Zurich sunspot group morphological classifications
• Revisiting Kunitomo's Sunspot Drawings during 1835-1836 in Japan
• Sunspot Drawings by Japanese Official Astronomers in 1749-1750
• Sunspot observations by Charles Malapert during the period 1618-1626: a key dataset to understand solar activity before the Maunder minimum

Cited by in corpus (4)

• Re-calibration of the Sunspot Number: Status Report
• Reconstructing solar irradiance from historical Ca II K observations. I. Method and its validation
• Scrutinizing the relationship between plage areas and sunspot areas and numbers
• Revisiting Christoph Scheiner's Sunspot Records: a New Perspective on Solar Activity of the Early Telescopic Era