Sunspot Observations and Counting at Specola Solare Ticinese in Locarno Since 1957

Cortesi, S.; Cagnotti, Marco; Bianda, M.; Ramelli, R.; Manna, Andrea

doi:10.1007/s11207-016-0872-7

Cited by 18 publications

(11 citation statements)

References 3 publications

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“…Indeed, Clette et al (2014), Svalgaard, Cagnotti, andCortesi (2017) conclude that this alternate counting method is the most likely cause of the 1947 scale jump in the original SN series. However, the timing and sharpness of the jump seem to be contradicted by the fact that this weighting practice was introduced progressively well before 1947, in the early 20th century by Wolfer (Cortesi et al, 2016;Svalgaard, Cagnotti, and Cortesi, 2017). Although Wolfer himself never used it for his own counts (Svalgaard, Cagnotti, and Cortesi, 2017), this practice was implemented to help assistants aligning their raw counts on the reference of Wolfer, the primary observer.…”

Section: A Major Disruption: Zurich Observersmentioning

confidence: 99%

Reconstruction of the Sunspot Number Source Database and the 1947 Zurich Discontinuity

et al. 2021

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The recalibration of the sunspot number series, the primary long-term record of the solar cycle, requires the recovery of the entire collection of raw sunspot counts collected by the Zurich Observatory for the production of this index between 1849 and 1980.Here, we report about the major progresses accomplished recently in the construction of this global digital sunspot number database, and we derive global statistics of all the individual observers and professional observatories who provided sunspot data over more than 130 years.First, we can announce the full recovery of long-lost source-data tables covering the last 34 years between 1945 and 1979, and we describe the unique information available in those tables. We then also retrace the evolution of the core observing team in Zurich and of the auxiliary stations. In 1947, we find a major disruption in the composition of both the Zurich team and the international network of auxiliary stations.This sharp transition is unique in the history of the Zurich Observatory and coincides with the main scale-jump found in the original Zurich sunspot number series, the so-called “Waldmeier” jump. This adds key historical evidence explaining why methodological changes introduced progressively in the early 20th century could play a role precisely at that time. We conclude on the remaining steps needed to fully complete this new sunspot data resource.

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Section: A Major Disruption: Zurich Observersmentioning

confidence: 99%

Reconstruction of the Sunspot Number Source Database and the 1947 Zurich Discontinuity

et al. 2021

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“…The first article in this section, by Vaquero et al (2016), represents one of the key outputs of the sunspotnumber workshops: the revised Schatten (1998a, 1998b) group sunspot number data base (1610 -present). This section also contains valuable reports from the longstanding observatories at Locarno (since 1957;Cortesi et al, 2016), Debrecen (since 1958; Baranyi, Gyori, andKanzelhöhe (since 1943;Pötzi et al, 2016), as well as a description of the ≈ ten-year record (2003 -2012) of sunspot numbers obtained by the ISOON telescope (Balasubramaniam and Henry, 2016).…”

Section: Organization and Brief Commentarymentioning

confidence: 99%

Preface to Topical Issue: Recalibration of the Sunspot Number

et al. 2016

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This topical issue contains articles on the effort to recalibrate the sunspot number (SN) that was initiated by the Sunspot Number Workshops. These workshops led to a revision of the Wolf sunspot number (WSN) and a new construction of the group sunspot number (GSN), both published herein. In addition, this topical issue includes three independently proposed alternative SN time series (two Wolf and one group), as well as articles providing historical context, critical assessments, correlative analyses, and observational data, both historical and modern, pertaining to the sunspot-number time series. The ongoing effort to understand and reconcile the differences between the various new sunspot number series is briefly discussed.

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“…However, there are several historical examples of single astronomers with a long observation series. For example, this is the case of Hisako Koyama with 37 observation years (Koyama, 1985;Knipp et al, 2017), David Hadden with 42 years (Carrasco et al, 2013), Sergio Cortesi with 55 years (Cortesi et al, 2016;Clette et al, 2016), and Thomas Cragg and Herbert Luft with 63 and 65 observation years respectively (Vaquero et al, 2016). These long data series provided by single observers are particularly valuable in order to maintain the homogeneity of the sunspot number series, even more valuable than institutional observatories performing their observations with multiple shifts (Clette et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

Eric Strach: Four Decades of Detailed Synoptic Solar Observations (1969‐2008)

2019

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Eric H. Strach (1914‐2011) studied medicine at University of Prague and graduated in 1938. Strach dedicated a great part of his life to astronomy becoming a consistent and meticulous observer. He joined the Liverpool Astronomical Association and British Astronomical Association during the 1960s and obtained two recognitions as proof of his great work in solar physics: the BAA's Merlin Medal and Gift in 1999 and Walter Goodacre Medal and Gift, 10 years later. Strach recorded four decades (1969‐2008) of systematic solar records in his observation notebooks although he started his observations from the late 1950s. In this work, we document the valuable effort made by Strach in getting four decades of solar records and the importance of this kind of long observation series for studies of space weather and climate. We present the sunspot group number series according to Strach's data and a long observation series of prominences recorded by Strach.

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Sunspot Observations and Counting at Specola Solare Ticinese in Locarno Since 1957

Cited by 18 publications

References 3 publications

Reconstruction of the Sunspot Number Source Database and the 1947 Zurich Discontinuity

Reconstruction of the Sunspot Number Source Database and the 1947 Zurich Discontinuity

Preface to Topical Issue: Recalibration of the Sunspot Number

Eric Strach: Four Decades of Detailed Synoptic Solar Observations (1969‐2008)

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