Sunspot Catalogue of the Valencia Observatory (1920 – 1928)

Carrasco, V. M. S.; Vaquero, J. M.; Aparicio, A. J. P.; Gallego, M. C.

doi:10.1007/s11207-014-0578-7

Cited by 20 publications

(13 citation statements)

References 25 publications

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“…Furthermore, these catalogues contain other valuable information about solar activity as, for example, the heliographic coordinates of the active regions. An important effort has been made during the last years to recover some sunspot catalogues (Willis et al, 2013, Casas andCarrasco et al, 2014;Baranyi, Győri, and Ludmány, 2016;Lefèvre et al, 2016;Mandal et al, 2017). However, the scientific community currently possesses a limited number of historical sunspot catalogues.…”

Section: Introductionmentioning

confidence: 99%

A Curious History of Sunspot Penumbrae: An Update

et al. 2018

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The ratio of penumbral to umbral area of sunspots is an important topic for solar and geophysical studies. Hathaway (Solar Physics, 286, 347, 2013) found a curious behaviour in this parameter for small sunspot groups (areas smaller than 100 millionths of solar hemisphere, msh) using records from Royal Greenwich Observatory (RGO). Hathaway showed that penumbra-umbra ratio decreased smoothly from more than 7 in 1905 to lower than 3 by 1930 and then increased to almost 8 in 1961. Thus, Hathaway proposed the existence of a secular variation in the penumbra-umbra area ratio. In order to confirm that secular variation, we employ data of the sunspot catalogue published by the Coimbra Astronomical Observatory (COI) for the period 1929-1941.Our results disagree with the penumbra-umbra ratio found by Hathaway for that period.However, the behaviour of this ratio for large (areas greater or equal than 100 msh) and small groups registered in COI during 1929-1941 is similar to data available from RGO for the periods 1874-1914 and 1950-1976. Nevertheless, while the average values and time evolution of the ratio in large groups is similar to the ratio for small groups according to Coimbra data (1929)(1930)(1931)(1932)(1933)(1934)(1935)(1936)(1937)(1938)(1939)(1940)(1941) it is not analogous for RGO data for the same period. We also found that the behaviour of the penumbra-umbra area ratio for smaller groups in both observatories is significantly different. The main difference between the area measurements made in Coimbra and RGO is associated with the umbra measurements. We would like to stress that the two observatories used different methods of observation and while in COI both methodology and instruments did not change during the study period, some changes were carried out in RGO that could have V.M.S. Carrasco et al.2 affected measurements of umbra and penumbra. These facts illustrate the importance of the careful recovery of past solar data.

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Section: Introductionmentioning

confidence: 99%

A Curious History of Sunspot Penumbrae: An Update

et al. 2018

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“…It has a temporal coverage of 74.0% during the period of study. Carrasco et al (2014) recently provided a machine-readable version of this catalogue. For the sunspot groups, the Valencia Observatory adopted the classification proposed by Cortie (1901).…”

Section: Cortie and Zürich Classificationsmentioning

confidence: 99%

Equivalence Relations Between the Cortie and Zürich Sunspot Group Morphological Classifications

et al. 2015

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Catalogues of sunspots have been available with useful information about sunspots or sunspot groups for approximately the last 150 years. However, the task of merging these catalogues is not simple. In this paper, a method is suggested of converting the types of sunspot groups that were proposed by Cortie (1901) into the well-known Zürich types of sunspot groups. To achieve this, the sunspot catalogue of the Valencia University Observatory (from 1920 to 1928) was used in addition to the descriptions proposed by Cortie. To assess the quality of this conversion scheme, the Zürich type was computed from the Valencia catalogue, and the resulting contribution of each group type was compared to what can be found in other catalogues. The results show that the proposed scheme works well within the errors that are found in the different catalogues.

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“…The reference observatory in sunspot observations during the 20th century and the last quarter of the 19th century was the Royal Greenwich Observatory (Erwin et al, ; Willis et al, ; Willis et al, ; Willis et al, ). Other important historical observatories of that time related with the sunspot observations were, for example, Mount Wilson (Lefebvre et al, ), Kodaikanal (Mandal et al, ), Debrecen (Baranyi et al, ), and the Iberian observatories (Aparicio et al, ; Carrasco et al, ; Carrasco et al, ; Curto et al, ). However, there are several historical examples of single astronomers with a long observation series.…”

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 Catalogue of the Valencia Observatory (1920 – 1928)

Cited by 20 publications

References 25 publications

A Curious History of Sunspot Penumbrae: An Update

A Curious History of Sunspot Penumbrae: An Update

Equivalence Relations Between the Cortie and Zürich Sunspot Group Morphological Classifications

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

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