82 citations · 273 across the 13 of their papers we have counts for
13 papers
Strong evidence of low levels of solar activity during the Maunder Minimum
V. M. S. Carrasco, H. Hayakawa, C. Kuroyanagi +2
The Maunder Minimum (MM) was a period of prolonged solar activity minimum between 1645 and 1715. Several works have identified a significant number of problematic spotless days in…
A limit for the values of the Dst geomagnetic index
F. J. Acero, J. M. Vaquero, M. C. Gallego +1
The study of the extreme weather space events is important for a technological dependent society. Extreme Value Theory could be decisive to characterize those extreme events in ord…
Soonspot: Software to Determine Areas and Sunspot Positions
P. Galaviz, V. M. S. Carrasco, F. Sánchez-Bajo +2
A new software (Soonspot) for the determination of the heliographic coordinates and areas of sunspots from solar images is presented. This program is very user-friendly and the acc…
Sunspot Catalogue of the Observatory of the University of Coimbra (1929-1941)
V. M. S. Carrasco, J. M. Vaquero, M. C. Gallego +3
A sunspot catalogue was published by the Coimbra Astronomical Observatory (Portugal), now named Geophysical and Astronomical Observatory of the University of Coimbra, for the perio…
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…
Analysing the spotless days as predictors of the solar activity from the new sunspot number
V. M. S. Carrasco, J. M. Vaquero, M. C. Gallego
The use of the spotless days to predict the future solar activity is here revised based on the new version of the sunspot number index with a 24-month filter. Data from Solar Cycle…
A Normalized Sunspot-Area Series Starting in 1832: an Update
V. M. S. Carrasco, J. M. Vaquero, M. C. Gallego +1
A new normalized sunspot-area series has been reconstructed from the series obtained by the Royal Greenwich Observatory and other contemporary institutions for the period 1874 - 20…
Monitoring the Solar Radius from the Royal Observatory of the Spanish Navy during the Last Quarter-Millennium
J. M. Vaquero, M. C. Gallego, J. J. Ruiz-Lorenzo +5
The solar diameter has been monitored at the Royal Observatory of the Spanish Navy (today the Real Instituto y Observatorio de la Armada: ROA) almost continuously since its creatio…
Level and length of cyclic solar activity during the Maunder minimum as deduced from the active day statistics
J. M. Vaquero, G. A. Kovaltsov, I. G. Usoskin +2
The Maunder minimum (MM) of greatly reduced solar activity took place in 1645-1715, but the exact level of sunspot activity is uncertain as based, to a large extent, on historical…
Reconstructing Past Solar Activity using Meridian Solar Observations: the Case of the Royal Observatory of the Spanish Navy (1833-1840)
J. M. Vaquero, M. C. Gallego
Solar meridian observations have been used to evaluate the solar activity of the past. Some important examples are the solar meridian observations made at the Basilica of San Petro…