158 citations · 651 across the 25 of their papers we have counts for
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A Sunspot Catalog for the Period 1952-1986 from Observations Made at the Madrid Astronomical Observatory
A. J. P. Aparicio, L. Lefèvre, M. C. Gallego +5
Sunspot catalogs are very useful for studying the solar activity of the recent past. In this context, a catalog covering more than three solar cycles made by the astronomers of the…
The umbra-penumbra area ratio of sunspots during the Maunder Minimum
V. M. S. Carrasco, J. M. García-Romero, J. M. Vaquero +4
The Maunder Minimum (MM) was a prolonged period of low solar activity that occurred between 1645 and 1715. The true level of solar activity corresponding to this epoch is still a m…
A Curious History of Sunspot Penumbrae: An Update
V. M. S. Carrasco, J. M. Vaquero, R. M. Trigo +1
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 thi…
Extreme value theory applied to the millennial sunspot number series
F. J. Acero, M. C. Gallego, J. A. García +2
In this work, we use two decadal sunspot number series reconstructed from cosmogenic radionuclide data (14C in tree trunks, SN-14C and 10Be in polar ice, SN-10Be) and the Extreme V…