A Sunspot Catalog for the Period 1952 – 1986 from Observations Made at the Madrid Astronomical Observatory

Aparicio, A. J. P.; Lefèvre, Laure; Gallego, M. C.; Vaquero, José M.; Clette, F.; Bravo-Paredes, Nieves; Galaviz, P.; Bautista, M. L.

doi:10.1007/s11207-018-1387-1

Cited by 9 publications

(8 citation statements)

References 23 publications

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“…The Madrid Astronomical Observatory made regular sunspot observations from 1876 to 1986, although some gaps can be found in this series (Aparicio et al 2014(Aparicio et al , 2018Lefèvre et al 2016). While daily data are available for the periods 1876-1896 and 1935-1986, only monthly data could be retrieved for the remaining observational periods.…”

Section: Introductionmentioning

confidence: 99%

Hemispheric Sunspot Number from the Madrid Astronomical Observatory for the Period 1935–1986

Aparicio

Carrasco

Gallego

et al. 2022

ApJ

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Long-term studies on hemispheric asymmetry can help to understand better the solar dynamo. We present the hemispheric sunspot number calculated from daily sunspot observations made at the Madrid Astronomical Observatory for the period 1935–1986 (corresponding approximately to Solar Cycles 17–21). From this data set, we also analyzed the asymmetry index and hemispheric phase shifts. We conclude that the northern hemisphere was predominant in Solar Cycles 17–20, whereas the southern hemisphere was predominant in Solar cycle 21. The strongest asymmetries are found in Solar Cycles 20 (with a relative difference between both hemispheres of 44%) and 19 (39%). A normalization of the Madrid hemispheric sunspot number was also made with respect to the sunspot number (Version 2). Our results agree with previous studies on hemispheric asymmetry around the mid-20th century and their secular trends.

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Section: Introductionmentioning

confidence: 99%

Hemispheric Sunspot Number from the Madrid Astronomical Observatory for the Period 1935–1986

Aparicio

Carrasco

Gallego

et al. 2022

ApJ

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“…On the other hand, the digitized catalogues available mainly contain data on sunspots (e.g. Aparicio et al, 2018;Carrasco et al, 2018bCarrasco et al, , 2014.…”

Section: Resultsmentioning

confidence: 99%

Testing the Accuracy of Coimbra Astronomical Observatory Solar Filament Historical Series (1929–1941)

et al. 2021

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The present work aims to validate the positions of solar filaments published in the Annals of Coimbra University Astronomical Observatory, currently the Geophysical and Astronomical Observatory of the University of Coimbra, corresponding to years 1929 to 1941. The published Stonyhurst positions were obtained by an original method devised in the early 20th century that used a spherical calculator instrument, a wood-made model of the Sun. We used the digital images of the original spectroheliograms to measure the positions of the filaments, and heliographic coordinates were determined with the routines implemented in the Python package Sunpy. The correlation coefficients between both sets of coordinates are positive and highly significant. The results validate the method used at the Coimbra observatory and the published data. We conclude that the Coimbra solar filament catalogues are reliable and can therefore be considered for future solar activity studies.

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“…Moreover, several sunspot catalogs were published by the observatory: the Aguilar catalog covering observations from 1914 to 1920 (Lefèvre et al, 2016), the Carrasco catalog including records for the period 1931 -1933 (Aparicio et al, 2022a), and the "modern" catalog with observations for 1952-1986(Aparicio et al, 2018. In addition to the sunspot observations, other solar features of the Sun were observed at the Madrid Astronomical Observatory such as prominences and chromospheric faculae (flocculi) (López Arroyo, 2004).…”

Section: Introductionmentioning

confidence: 99%

Rediscovering the observations of solar prominences from 1906 to 1957 recorded at the Madrid Astronomical Observatory

Aparicio¹,

Carrasco²,

Gallego³

et al. 2023

J. Space Weather Space Clim.

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The Madrid Astronomical Observatory implemented a solar observation program from 1876 to 1986. In addition to sunspots, the observers at this observatory recorded other solar features such as prominences. In this work, we have consulted the documentary sources of the Madrid Astronomical Observatory (the information is not digitally available), digitized the records of the observers on the annual number of prominences, and constructed a homogeneous series of the total and hemispheric annual number of prominences with heights of 25’’ and more for the period 1906 – 1957. To evaluate the quality of the data and assess their potential, we have compared the Madrid prominence series with the number of prominences recorded by the Astronomical Observatory of the University of Coimbra and other time series such as the sunspot number index, solar radio flux at 10.7 cm, and sunspot areas. We have also analyzed the hemispheric prominence numbers and the asymmetry index. We obtained the strongest correlation between Madrid and Coimbra prominence series (r = 0.7), whereas the correlations between Madrid prominence series and the other solar activity time series are similar (r ≈ 0.6). In addition, we found that the correlation coefficient between the Madrid prominence series and the sunspot number is lower than that from Coimbra prominence series and the sunspot number. We suggest that these differences are a consequence of the way prominences were counted in the Madrid Astronomical Observatory.

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A Sunspot Catalog for the Period 1952 – 1986 from Observations Made at the Madrid Astronomical Observatory

Cited by 9 publications

References 23 publications

Hemispheric Sunspot Number from the Madrid Astronomical Observatory for the Period 1935–1986

Hemispheric Sunspot Number from the Madrid Astronomical Observatory for the Period 1935–1986

Testing the Accuracy of Coimbra Astronomical Observatory Solar Filament Historical Series (1929–1941)

Rediscovering the observations of solar prominences from 1906 to 1957 recorded at the Madrid Astronomical Observatory

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