scholarly journals Reanalyses of the sunspot observations of Fogelius and Siverus: Two “Long-Term” observers during the Maunder Minimum

2020 ◽  
Author(s):  
Hisashi Hayakawa ◽  
Tomoya Iju ◽  
Shoma Uneme ◽  
Bruno P Besser ◽  
Shunsuke Kosaka ◽  
...  
Keyword(s):  
Sunspot Group ◽  
Maunder Minimum ◽  
Solar Cycles ◽  
Observational Period ◽  
The Core ◽  
Cycle Amplitude ◽  
Group Number ◽  
The One ◽  
Sunspot Groups

Abstract The solar activity during the Maunder Minimum (MM; 1645–1715) has been considered significantly different from the one captured in modern observations, in terms of sunspot group number and sunspot positions, whereas its actual amplitudes and distributions is still under active discussions. In its core period (1650/1660–1700), Martin Fogelius and Henrich Siverus have formed significant long-term series in the existing databases with numerous spotless days, as the 13th and 7th most active observers before the end of the MM. In this study, we have analysed their original archival records, revised their data, have removed significant contaminations of the apparent ‘spotless days’ in the existing databases, and cast caveats on the potential underestimation of the solar-cycle amplitude in the core MM. Still, they reported at best one sunspot group throughout their observational period and confirm the significant suppressed the solar cycles during the MM, which is also supported from the contemporary observations of Hook and Willoughby. Based on the revised data, we have also derived positions of notable sunspot groups, which Siverus recorded in 1671 (≈ N7.5° ± 2.5°), in comparison with those of Cassini's drawings (≈ N10° ± 1°). Their coincidence in position and chronology in corrected dates indicates these sunspot groups were probably the same recurrent active region (AR) and its significantly long lifespan (≥ 35 days) even during the MM.

Number of Sunspot Groups and Individual Sunspots Recorded by Tevel for the Period 1816–1836 in the Dalton Minimum

2021 ◽  
Vol 922 (1) ◽  
pp. 58
Author(s):  
V. M. S. Carrasco
Keyword(s):  
Solar Cycle ◽  
Sunspot Number ◽  
Sunspot Group ◽  
Maunder Minimum ◽  
The Other ◽  
Solar Cycles ◽  
Group Number ◽  
The One ◽  
Dalton Minimum ◽  
Sunspot Groups

Abstract Cornelis Tevel made sunspot observations during the period 1816–1836, including the Dalton Minimum. In this work, the first revision of these observations since Wolf incorporated them into his database is presented. On the one hand, the number of individual sunspots from Tevel’s drawings was counted. This is of special interest for the sunspot number reconstruction because this kind of information is not as common in historical sunspot records as the number of groups. Thus, Tevel could be considered for the future reconstruction of the sunspot number index. On the other hand, the number of groups counted according to modern sunspot group classifications finding significant misinterpretations with the number of groups assigned to Tevel in the existing databases. Tevel was a relevant sunspot observer in the Dalton Minimum. In fact, he was the observer with the highest number of groups observed in Solar Cycles 6 and 7 according to the existing sunspot group number databases. According to the raw group number recount in this work, the maximum amplitudes for Solar Cycles 6 and 7 are, respectively, 27% and 7% lower than those previously determined. Moreover, Solar Cycle 6 is the weakest solar cycle since the Maunder Minimum after applying these new counts. Group counts from Tevel’s observations were compared with those from relevant contemporary astronomers, demonstrating that Schwabe and Tevel systematically recorded a higher number of groups than Flaugergues and Derfflinger. In addition, sunspot areas and positions recorded by Tevel should be used with caution for scientific purposes.

scholarly journals Sunspot group tilt angles from drawings for cycles 19-24

2018 ◽  
Vol 13 (S340) ◽  
pp. 133-136 ◽  
Author(s):  
Emre Işık ◽  
Seda Işık ◽  
Bahar B. Kabasakal
Keyword(s):  
Magnetic Flux ◽  
Tilt Angle ◽  
Group Selection ◽  
Selection Criteria ◽  
Sunspot Group ◽  
Solar Dynamo ◽  
Solar Cycles ◽  
Surface Transport ◽  
Sunspot Groups

AbstractThe tilt angle of a sunspot group is a critical quantity in the surface transport of magnetic flux and the solar dynamo. To contribute long-term databases of the tilt angle, we developed an IDL routine, which allows the user to interactively select and measure sunspot positions and areas on the solar disc. We measured the tilt angles of sunspot groups for solar cycles 19-24 (1954.6-2017.8), using the sunspot drawing database of Kandilli Observatory. The method is similar to that used in the discontinued Mt. Wilson and Kodaikanal databases, with the exception that sunspot groups were identified manually, which has improved the accuracy of the resulting tilt angles. We obtained cycle averages of the tilt angle and compared them with the values from other datasets, keeping the same group selection criteria. We conclude that the previously reported anti-correlation with the cycle strength needs further investigation.

Sunspot and Group Number: Recent advances from historical data

2018 ◽  
Vol 14 (A30) ◽  
pp. 156-159 ◽  
Author(s):  
Frédéric Clette ◽  
José M. Vaquero ◽  
María Cruz Gallego ◽  
Laure Lefèvre
Keyword(s):  
Sunspot Number ◽  
Maunder Minimum ◽  
Current Data ◽  
Activity Level ◽  
Historical Evidence ◽  
The Earth ◽  
Earth Environment ◽  
Group Number ◽  
Dalton Minimum

AbstractDue to its unique 400-year duration, the sunspot number is a central reference for understanding the long-term evolution of solar activity and its influence on the Earth environment and climate. Here, we outline current data recovery work. For the sunspot number, we find historical evidence of a disruption in the source observers occurring in 1947–48. For the sunpot group number, recent data confirm the clear southern predominance of sunspots during the Maunder Minimum, while the umbra-penumbra ratio is similar to other epochs. For the Dalton minimum, newly recovered historical observations confirm a higher activity level than in a true Grand Minimum.

Integrating Web 2.0 Technologies within the Enterprise

2010 ◽  
pp. 560-577
Author(s):  
R. Todd Stephens
Keyword(s):  
Life Cycle ◽  
Web 2.0 ◽  
Global Economy ◽  
New Technologies ◽  
Lessons Learned ◽  
The Core ◽  
Collaborative Applications ◽  
Current Product ◽  
The One

This chapter examines the elements of the new Web 2.0 technology base and reviews the lessons learned when implementing these technologies. Collaborative applications have made enormous inroads into the enterprise and bring unprecedented speed and transparency to communications. Researchers and practitioners alike are focusing on how collaborative applications can replace the one-way communications inherent to Intranet sites. This chapter is intended for individuals who are looking toward the possibility of integrating these new technologies into the core communication medium. Unfortunately, there are still large barriers such as politics, turf battles, integration, and poor usability with the current product set. A company’s ability to manage information effectively over its life cycle, including sensing, collecting, organizing, processing, and maintaining information, is crucial to the long term success in a global economy. The success or failure of this integration may very well create or lose a competitive advantage for the enterprise. What is missing is a framework or roadmap in which organizations can plan out their execution of We 2.0 deployment.

scholarly journals In-depth survey of sunspot and active region catalogs

2010 ◽  
Vol 6 (S273) ◽  
pp. 221-225 ◽  
Author(s):  
Laure Lefèvre ◽  
Frédéric Clette ◽  
Tunde Baranyi
Keyword(s):  
Active Region ◽  
Sunspot Group ◽  
Solar Cycles ◽  
Time Intervals ◽  
Long Time ◽  
Comprehensive Survey ◽  
Central Database ◽  
Index Time Series ◽  
Activity Indices ◽  
Sunspot Groups

AbstractWhen consulting detailed photospheric catalogs for solar activity studies spanning long time intervals, solar physicists face multiple limitations in the existing catalogs: finite or fragmented time coverage, limited time overlap between catalogs and even more importantly, a mismatch in contents and conventions. In view of a study of new sunspot-based activity indices, we have conducted a comprehensive survey of existing catalogs.In a first approach, we illustrate how the information from parallel catalogs can be merged to form a much more comprehensive record of sunspot groups. For this, we use the unique Debrecen Photoheliographic Data (DPD), which is already a composite of several ground observatories and SOHO data, and the USAF/Mount Wilson catalog from the Solar Optical Observing Network (SOON). We also describe our semi-interactive cross-identification method, which was needed to match the non-overlapping solar active region nomenclature, the most critical and subtle step when working with multiple catalogs. This effort, focused here first on the last two solar cycles, should lead to a better central database collecting all available sunspot group parameters to address future solar cycle studies beyond the traditional sunspot index time series Ri.

scholarly journals Comparison of the shape and temporal evolution of even and odd solar cycles

2020 ◽  
Vol 636 ◽  
pp. A11
Author(s):  
Jouni Takalo ◽  
Kalevi Mursula
Keyword(s):  
Sunspot Group ◽  
Temporal Evolution ◽  
Sunspot Area ◽  
Distribution Analysis ◽  
Solar Cycles ◽  
Sunspot Numbers ◽  
Group Data ◽  
Odd Cycles ◽  
Skewness And Kurtosis ◽  
Sunspot Groups

Aims. We study the difference in the shape of solar cycles for even and odd cycles using the Wolf sunspot numbers and group sunspot numbers of solar cycles 1−23. We furthermore analyse the data of sunspot area sizes for even and odd cycles SC12−SC23 and sunspot group data for even and odd cycles SC8−SC23 to compare the temporal evolution of even and odd cycles. Methods. We applied the principal component analysis (PCA) to sunspot cycle data and studied the first two components, which describe the average cycle shape and cycle asymmetry. We used a distribution analysis to analyse the temporal evolution of the even and odd cycles and determined the skewness and kurtosis for even and odd cycles of sunspot group data. Results. The PCA confirms the existence of the Gnevyshev gap (GG) for solar cycles at about 40% from the start of the cycle. The temporal evolution of sunspot area data for even cycles shows that the GG exists at least at the 95% confidence level for all sizes of sunspots. On the other hand, the GG is shorter and statistically insignificant for the odd cycles of aerial sunspot data. Furthermore, the analysis of sunspot area sizes for even and odd cycles of SC12−SC23 shows that the greatest difference is at 4.2−4.6 years, where even cycles have a far smaller total area than odd cycles. The average area of the individual sunspots of even cycles is also smaller in this interval. The statistical analysis of the temporal evolution shows that northern sunspot groups maximise earlier than southern groups for even cycles, but are concurrent for odd cycles. Furthermore, the temporal distributions of odd cycles are slightly more leptokurtic than distributions of even cycles. The skewnesses are 0.37 and 0.49 and the kurtoses 2.79 and 2.94 for even and odd cycles, respectively. The correlation coefficient between skewness and kurtosis for even cycles is 0.69, and for odd cycles, it is 0.90. Conclusions. The separate PCAs for even and odd sunspot cycles show that odd cycles are more inhomogeneous than even cycles, especially in GSN data. Even cycles, however, have two anomalous cycles: SC4 and SC6. The variation in the shape of the early sunspot cycles suggests that there are too few and/or inaccurate measurements before SC8. According to the analysis of the sunspot area size data, the GG is more distinct in even than odd cycles. This may be partly due to sunspot groups maximizing earlier in the northern than in the southern hemisphere for even cycles. We also present another Waldmeier-type rule, that is, we find a correlation between skewness and kurtosis of the sunspot group cycles.

Legitimacy of the Modern Age?

2014 ◽  
Author(s):  
Alexander Schmitz
Keyword(s):  
Political Theology ◽  
Modern Science ◽  
The Self ◽  
Carl Schmitt ◽  
Western Modernity ◽  
The Core ◽  
Hans Blumenberg ◽  
Modern Age ◽  
The One

The opposition between religiosity and secularism is the key to both a discourse-historical epochal threshold and the question of the self-understanding of Western modernity. The controversy between Carl Schmitt and Hans Blumenberg constitutes one episode in the long-term, many-faceted debate over secularization. At the core of the controversy is the question of how modern science on the one hand and rational law on the other hand can be differentiated as autonomous realms. At the same time, the anthropological framing conditions for a technologized life world are here at issue. Carl Schmitt began the controversy in the afterword of his last book, which criticized Blumenberg’s Legitimacy of the Modern Age in a basic way. Political Theology II thus also became Schmitt’s testament, in which he formulated instructions about how to read the continuity and identity of his life and work.

Integrating Web 2.0 Technologies within the Enterprise

2011 ◽  
pp. 201-218
Author(s):  
R. Todd Stephens
Keyword(s):  
Life Cycle ◽  
Web 2.0 ◽  
Global Economy ◽  
New Technologies ◽  
Lessons Learned ◽  
The Core ◽  
Collaborative Applications ◽  
Current Product ◽  
The One

This chapter examines the elements of the new Web 2.0 technology base and reviews the lessons learned when implementing these technologies. Collaborative applications have made enormous inroads into the enterprise and bring unprecedented speed and transparency to communications. Researchers and practitioners alike are focusing on how collaborative applications can replace the one-way communications inherent to Intranet sites. This chapter is intended for individuals who are looking toward the possibility of integrating these new technologies into the core communication medium. Unfortunately, there are still large barriers such as politics, turf battles, integration, and poor usability with the current product set. A company’s ability to manage information effectively over its life cycle, including sensing, collecting, organizing, processing, and maintaining information, is crucial to the long term success in a global economy. The success or failure of this integration may very well create or lose a competitive advantage for the enterprise. What is missing is a framework or roadmap in which organizations can plan out their execution of We 2.0 deployment.

scholarly journals Number of sunspot groups from the Galileo–Scheiner controversy revisited

2020 ◽  
Vol 496 (2) ◽  
pp. 2482-2492
Author(s):  
V M S Carrasco ◽  
M C Gallego ◽  
J M Vaquero
Keyword(s):  
Sunspot Group ◽  
Observational Methods ◽  
Current Group ◽  
Galileo Galilei ◽  
Documentary Sources ◽  
Group Number ◽  
Observation Series ◽  
Temporal Coverage ◽  
Sunspot Groups

ABSTRACT We revise the sunspot observations made by Galileo Galilei and Christoph Scheiner in the context of their controversy regarding the nature of sunspots. Those of their sunspot records not included in the current sunspot group database, used as a basis to calculate the sunspot group number, are analysed. Within the documentary sources consulted in this work, we can highlight the sunspot observations by Scheiner included in the letters sent under the pseudonym Apelles to Marcus Welser and the first sunspot observations made by Galileo, which can be consulted in Le opere di Galileo Galilei. These sunspot observations would extend the temporal coverage for these two observers and fill some gaps in the current group database in the earliest period, where the data available are sparse. Moreover, we have detected changes in the quality of the sunspot drawings made by Galileo and Scheiner in their observation series, affecting the number of groups recorded by the two observers. We also compare these records with sunspot observations made by other astronomers of that time. According to this comparison and regarding the same observation days, Scheiner was generally the astronomer who reported more sunspot groups, while Harriot, Cigoli and Galileo recorded a similar number of groups. We conclude that these differences are mainly because of the observational methods used by the observers.

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