José M. Vaquero

Universidad de Extremadura | UNEX · Department of Physics

Past solar activity is of great interest for astrophysical and geophysical studies. Systematic searches over the last four centuries have detailed the evolution of the solar cycle. Brief comments on solar activity for periods with sparse records, such as the year 1791, are crucial. Lorenzo Hervás y Panduro, a Jesuit intellectual, noted in his 1793...

The Maunder Minimum was a period with significantly reduced solar activity between 1645 and 1715, approximately. The transition between the low solar activity in the Maunder Minimum and the subsequent “normal” regime of solar activity was gradual. However, there are discrepancies in the solar activity level from sunspot number indices and solar act...

The Leonid meteor shower is renowned for its scientific and public interest. In a search for meteorological data from Portuguese stations, records on an observation of the Leonids in 1869 from the Lisbon Geophysical Observatory “Infante Dom Luiz” were found. Given their potential value, a digital version with metadata is provided in the present not...

We recover a report in the “HOY” regional newspaper about a presumed meteorite fall near Cabeza la Vaca, Spain. The report details observable effects like a crater, uprooted tree, and a destroyed fence. While the exact date is unknown, it likely occurred within a week of 1970 January 27. The report lacks the crater size specification. This research...

Within four centuries of sunspot observations, the Maunder Minimum (MM) in 1645–1715 has been considered a unique grand minimum with weak solar cycles in group numbers of sunspots and hemispheric asymmetry in sunspot positions. However, the early part of the MM (1645–1659) is poorly understood in terms of its source records and has accommodated div...

In a routine search for meteorological events with a great impact on society in the Extremadura region (SW interior of Iberia) using newspapers, the month of June 1925 was detected as exceptional due to the large number of electrical storms that occurred and the significant impacts that caused, with serious losses in human lives and material resour...

The recovery of records of past solar observations is crucial to understand the evolution of solar activity. In this context, three records of sunspot observations made at the Royal Observatory of the Spanish Navy in 1789 January and July, and 1790 June are shown in the present work. The aim of the observers who performed these sunspot observations...

We discuss the discovery of a significant meteoric event over Don Benito, Spain, described in two news reports from the regional newspaper “Extremadura.” These reports detail intense light, loud noises, and shattered windows in Don Benito during 1926 December. Despite limited information, this research note aims to share the findings with the scien...

Early meteorological observations have been found for the period 1788–1813 in a collection of historical documents entitled “Medical and meteorological observation books” (Livros de observações médicas e meteorológicas) that is preserved nowadays in the Municipal Historical Archive of Almada. Almada is a Portuguese city located on the southern bank...

In this work, we predict the maximum amplitude (using the 13-month smoothed Solar Influences Data Analysis Center (SILSO) Sunspot Number, version 2) of Solar Cycle 25 using as a predictor the slope of the inflection point during the ascending part of the cycle. After a description of the data and methodology employed in this work, we obtain a value...

We have previously published several research notes analyzing the solar activity level of current Solar Cycle 25 from the observed sunspot data. pointing out that it exhibits the typical behavior of a weak-moderate cycle. We show in this updated analysis of the solar activity level for Solar Cycle 25 (three year after its beginning) that the curren...

In 1639, the German naturalist Georg Marcgraf established the first astronomical observatory in the Americas, located in Recife (Brazil). There, he made the first daily systematic meteorological observations of wind direction, precipitation, fog, and thunder and lightning from 1640 to 1642. We outline the circumstances that led to this observatory...

Cádiz and San Fernando are two towns close to each other with a wealth of meteorological records due to their connection with the Spanish Royal Navy officers and enlightened merchants. Several previous works have already recovered a significant number of meteorological records of interest in these localities. However, more than 40 000 daily meteoro...

Jos\'e D\'iaz Bejarano (1933-2019) was born in Puebla de la Calzada (Badajoz, Spain). He studied Chemistry in the University of Seville and Physics in the University of Madrid. Later, he developed a successful research career in several international centers including the University of Hamburg (Germany), CERN (Geneva, Switzerland) or Case Western R...

In this work, we present hemispheric sunspot number counts made in the Astronomical Observatory of the University of Valencia for the period 1940 – 1956. We found these data in a secondary source (the bulletins of the Madrid Astronomical Observatory). We digitized the hemispheric sunspot number and group number recorded by the observers. Unfortunat...

The search for correlations between secondary cosmic ray detection rates and seismic effects has long been a subject of investigation motivated by the hope of identifying a new precursor type that could feed a global early warning system against earthquakes. Here we show for the first time that the average variation of the cosmic ray detection rate...

We report progress on the ongoing recalibration of the Wolf sunspot number ( $S_{\mathrm{N}}$ S N ) and group-sunspot number ( $G_{\mathrm{N}}$ G N ) following the release of version 2.0 of $S_{\mathrm{N}}$ S N in 2015. This report constitutes both an update of the efforts reported in the 2016 Topical Issue of Solar Physics and a summary of work by...

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), digi...

This work analyses the long‐term temporal variability of the annual and seasonal series of reconstructed global solar radiation for both all‐sky and cloud‐free conditions in Badajoz (Spain) over the 1929–2015 period. Specifically, daily values of global horizontal irradiation (GHI) for all‐sky cases are derived from a semiempirical method based on...

Old physics textbooks give us a great opportunity to learn about the history of science and rediscover different methods to teach physics to our students. There are many disused and forgotten experiments in them, but these can still be very useful to affirm and understand physics. This is the case of an instrument used in the 19th century to demons...

We report progress on the ongoing recalibration of the Wolf sunspot number (SN) and Group sunspot number (GN) following the release of version 2.0 of SN in 2015. This report constitutes both an update of the efforts reported in the 2016 Topical Issue of Solar Physics and a summary of work by the International Space Science Institute (ISSI) Internat...

Cádiz and San Fernando are two nearby towns with a wealth of meteorological records due to their connection with the Spanish Royal Navy officers and enlightened merchants. Several previous works have already recovered a significant amount of meteorological records of interest in these localities. However, unnoticed previously more than 40,000 daily...

The Astronomical Observatory of the University of Coimbra (Portugal) published a catalog with solar observations such as sunspots, faculae, prominences, and filaments for the period 1929–1944. In previous works, a machine-readable version on sunspot observations made in Coimbra was published. Here we extend that work and present a digital version o...

A new open-source software, called SunMap, has been developed to obtain synoptic maps in an easy and quick way from multiple full-disc solar images. Our objective is to provide a free and straightforward application for heliophysicists and geophysicists interested in generating solar synoptic maps. SunMap allows comparison of structures and pattern...

We show in this note a simple exercise to overcome a common preconception among Geodesy students about the “best” reference ellipsoid. This helps students to overcome their previous ideas based on a purely geometric vision of the reference ellipsoids and advance to a more physical point of view, where the Earth’s gravity plays a fundamental role.

The flash flood registered in November 1997 in the city of Badajoz (Spain) in the basin of Rivillas river is analysed by means of the numerical code Iber+. This event constitutes one of the most destructive flash-floods registered in an urban area in the Iberian Peninsula. Starting from precipitation data obtained from rain stations, the runoff of...

Great advances in meteorological science were made in the late eighteenth century. In particular, meteorological instruments were carried on ships and the first systematic meteorological readings over the oceans were made. One of these collections of instrumental meteorological readings was carried out by the Malaspina expedition (1789–94), organiz...

Long-term solar activity can be studied using several parameters. Some of the most used are based on the sunspot counting. The active day fraction (ADF) is the simplest index derived from this counting. It is reliable in periods of low solar activity such as the Maunder minimum (MM). In this work, we study the relationship between the ADF and the s...

The effects of solar activity on technology have increased the interest in solar forecasting both in the scientific community and in society. With two and a half years of data available, we are approximately halfway to the maximum of Solar Cycle 25. Several research groups around the world published their predictions for this cycle. In this work, w...

A sunspot catalog was published by the Madrid Astronomical Observatory from sunspot observations made by Rafael Carrasco and his assistants for the period November 1931 – December 1933. We have digitized this catalog and carried out a quality control to detect inconsistencies. We present a machine-readable version of this sunspot catalog together w...

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 i...

The search for correlations between secondary cosmic ray detection rates and seismic effects has long been a subject of investigation motivated by the hope of identifying a new precursor type that could feed a global early warning system against earthquakes. Here we show for the first time that the average variation of the cosmic ray detection rate...

Great advances in meteorological science were made in the late 18th century. In particular, meteorological instruments were carried on ships and the first systematic meteorological readings over the oceans were made. One of these collections of instrumental meteorological readings was carried out by the Malaspina expedition (1789-1794), organized b...

The camera obscura is a well-known optical device in the form of a closed box with a hole in one of its walls through which light rays pass, forming an inverted image of the external objects on the opposite wall, as can be seen in Fig. 1(a). Despite the simplicity of its basic design, they have been widely used by scientists and artists. In particu...

The solar cycle periodically reshapes the magnetic structure and radiative output of the Sun and determines its impact on the heliosphere roughly every 11 years. Besides this main periodicity, it shows century-long variations (including periods of abnormally low solar activity called grand minima). The Maunder Minimum (1645-1715) has generated sign...

Christoph Scheiner was one of the most outstanding astronomers in the history of sunspot observations. His book, Rosa Ursina , is the reference work regarding the study of the earliest sunspot records. The sunspot observations compiled by Scheiner in Rosa Ursina and Prodomus , including records made by other observers, forms one of the main referen...

Jean Tarde and Jan Smogulecki carried out sunspot observations in the 1610s and 1620s at the dawn of the telescopic era. We analysed their original observational records to revise their sunspot-group numbers in the existing database. In this study, we provide a new counting as a basis for future scientific discussions. Furthermore, we compared Smog...

Angelo Secchi (1818-1878) was an Italian Jesuit who made relevant scientific contributions in the area of geophysics, meteorology and astrophysics. He was a well-known pioneer in solar physics due to his theories and observations. Secchi published in his book Le Soleil (The Sun) a summary of knowledge about our star in that time. Moreover, he publi...

A sunspot observation program was started at the end of the 19th century at the Stonyhurst College Observatory (hereafter SCO) by Father Perry, director of the observatory at that time. A digitization of the daily sunspot area series recorded in this observatory from 1886 to 1940 (with a gap between 1889 and 1897) is provided in this work. This dep...

In this work, we provide instrumental meteorological data recovered for the Extremadura region (interior SW Iberia), from 1826 to mid‐20th century. Meteorological variables such as air temperature, atmospheric pressure, precipitation, wind direction and humidity, among others, were retrieved. In total, more than 750 000 instrumental data in 157 met...

Solar Cycle 25 started in 2019 December. Different predictions for its amplitude have been published so far without general consensus. We compared the evolution of Solar Cycle 25, using the first available values of the smoothed sunspot number, with past solar cycles. Our analysis shows that Solar Cycle 25 is very similar to Solar Cycles 24 and 7....

Climate proxy data are required for improved understanding of climate variability and change in the pre-instrumental period. We present the first international initiative to compile and share information on pro pluvia rogation ceremonies, which is a well-studied proxy of agricultural drought. Currently, the database has more than 3500 dates of cele...

The task of retrieving information about past flood events is very important to reconstruct flood series data. In this work, a wide range of different sources including newspapers, technical reports, and books was consulted in order to recover information about catastrophic flood events in Badajoz (Spain). A set of 37 catastrophic floods of the Gua...

We have located a forgotten record of sunspot observations made by Jean Charles Gallet in the year 1677, in the middle of the Maunder Minimum (the period between 1645 and 1715 characterized by very low solar activity). Gallet observed one sunspot group from April 9 to 15 and another from October 1 to 6. While the group observed in April was also re...

A series of measurements of the solar diameter taken in the meridian line of the Basilica of San Petronio (Bologna, Italy) between 1655 and 1736 has been analyzed. This series is of interest because the measurement period includes the Maunder Minimum (1645–1715; hereafter MM) when solar activity was abnormally low. Some authors have suggested an in...

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 the MM included in existing databases. We have found a list of exact spotless (in the second half of 1709) and spot days (January and August 1709) provided by Johann Hein...

The recovery of early sunshine duration (SD) records is crucial to improve knowledge of the long‐term evolution of incoming solar radiation at the Earth's surface. This work analyses daily SD data digitized from the Meteorological Observatory of Coimbra (Portugal) during 1891–1950. The Coimbra SD records are the earliest series in Portugal and the...

Pierre Gassendi (1592 – 1655) carried out sunspot observations during the 1630s. This period is particularly interesting because it occurred a few years before the Maunder Minimum. Gassendi was the second most active sunspot observer in that decade, surpassed only by Christoph Scheiner. Moreover, the sunspot observations made by Gassendi are of int...

In recent decades, the development of numerical tools has facilitated the ability to reproduce extreme flood events, which allows a far better understanding of their features, contributing to mitigate their negative effects in similar future scenarios. This paper analyzes the flood event that occurred in December 1876 in Badajoz (Spain-Guadiana bas...

A revision is presented of the sunspot observations made by Charles Malapert from 1618 to 1626, studying several documentary sources that include those observations. The revised accounting of the group numbers recorded by Malapert for that period shows new information unavailable in the current sunspot group database. The average solar activity lev...

An analysis of the sunspot observations made by Hevelius during 1642-1645 is presented. These records are the only systematic sunspot observations just before the Maunder Minimum. We have studied different phenomena meticulously recorded by Hevelius after translating the original Latin texts. We re-evaluate the observations of sunspot groups by Hev...

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 wo...

William Cranch Bond, director of the Harvard College Observatory in mid-19th century, carried out detailed sunspot observations during the period 1847-1849. We highlight Bond was the observer with the highest daily number of sunspot groups observed in Solar Cycle 9 recording 18 groups on 26 December 1848 according to the current sunspot group datab...

We revise the sunspot observations made by Galileo Galilei and Christoph Scheiner in the context of their controversy on the nature of sunspots. Their sunspot records not included in the current sunspot group database, used as a basis to calculate the sunspot group number, are analyzed. Within the documentary sources consulted in this work, we can...

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 accuracy of its results has been checked by using solar images provided by the Debrecen Photoheliographic Data (DPD). Due to its applicability in the studies of historical s...

Antonio Colla was a meteorologist and astronomer who made sunspot observations at the Meteorological Observatory of the Parma University (Italy). He carried out his sunspot records from 1830 to 1843, just after the Dalton Minimum. We have recovered 71 observation days for this observer. Unfortunately, many of these records are qualitative and we co...

Newly discovered descriptions about the great aurora observed in March 1582 are presented in this work. These records were made by Portuguese observers from Lisbon. Both records described the aurora like a great fire in the northern part of the sky. It was observed during three consecutive nights, according to one of the sources. Thus, we present a...

A sunspot catalogue was published by the Coimbra Astronomical Observatory (Portugal), now named Geophysical and Astronomical Observatory of the University of Coimbra, for the period 1929-1941. We digitalized data included in that catalogue and provide a machine-readable version. We show the reconstructions for the (total and hemispheric) sunspot nu...

A complete dataset of sunspot drawings recorded at Sacramento Peak Observatory (SPO) from late 1947 till mid-2004 has been digitized. We present the history of the observations and describe the data included in the drawings. We compare the sunspot number index calculated from the SPO data and the International Sunspot Number (SNv2), and we find tha...

Sunspot observations are available in fairly good numbers since 1610, after the invention of the telescope. This review is concerned with those sunspot observations of which longer records and drawings in particular are available. Those records bear information beyond the classical sunspot numbers or group sunspot numbers. We begin with a brief sum...

The current pandemic of coronavirus disease 2019 (COVID-19) caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is having negative health, social and economic consequences worldwide. In Europe, the pandemic started to develop strongly at the end of February and beginning of March 2020. Subsequently, it spread over the contine...

Nearshore upwelling along the eastern North Atlantic margin regulates regional marine ecosystem productivity and thus impacts blue economies. While most global circulation models show an increase in the intensity and duration of seasonal upwelling at high latitudes under future human-induced warmer conditions, projections for the North Atlantic are...

Naked-eye sunspot observations (NESOs) have been recorded for the past two millennia, approximately. These kinds of records were made around the world, mainly in Asian civilizations, and they are compiled in several catalogs. In this work, we analyze solar activity on days of the 19th century when NESOs were recorded. We found that only more than f...

The Cosmic-Ray Extremely Distributed Observatory (CREDO) is a newly formed, global collaboration dedicated to observing and studying cosmic rays (CR) and cosmic-ray ensembles (CRE): groups of at least two CR with a common primary interaction vertex or the same parent particle. The CREDO program embraces testing known CR and CRE scenarios, and prepa...

Naked-eye sunspot observations (NESO, hereafter) have been recorded for last two millennia, approximately. This kind of records were made around the world, mainly in Asian civilizations, and they are compiled in several catalogues. In this work, we analyze solar activity in days of the 19th century when NESO were recorded. We found that only more t...

The Cosmic Ray Extremely Distributed Observatory (CREDO) is a newly formed, global collaboration dedicated to observing and studying cosmic rays (CR) and cosmic ray ensembles (CRE): groups of a minimum of two CR with a common primary interaction vertex or the same parent particle. The CREDO program embraces testing known CR and CRE scenarios, and p...

The Cosmic Ray Extremely Distributed Observatory (CREDO) is a newly formed, global collaboration dedicated to observing and studying cosmic rays (CR) and cosmic ray ensembles (CRE): groups of a minimum of two CR with a common primary interaction vertex or the same parent particle. The CREDO program embraces testing known CR and CRE scenarios, and p...

The Cosmic Ray Extremely Distributed Observatory (CREDO) is a newly formed, global collaboration dedicated to observing and studying cosmic rays (CR) and cosmic ray ensembles (CRE): groups of a minimum of two CR with a common primary interaction vertex or the same parent particle. The CREDO program embraces testing known CR and CRE scenarios, and p...

William Cranch Bond, director of the Harvard College Observatory in mid-19th century, carried out detailed sunspot observations during the period 1847–1849. We highlight Bond was the observer with the highest daily number of sunspot groups observed in Solar Cycle 9 recording 18 groups on 26 December 1848 according to the current sunspot group datab...

Antonio Colla was a meteorologist and astronomer who made sunspot observations at the Meteorological Observatory of the Parma University (Italy). He carried out his sunspot observations from 1830 to 1843, just after the Dalton Minimum. We have recovered 71 observation days for this observer. Unfortunately, many of these records are qualitative and...

This article presents the evolution of daily sunshine duration (SD) records at the San Fernando Observatory, a coastal place located in southern Iberian Peninsula, during the period 1881–1890. This period is of great interest because in August 1883, the Krakatoa volcano erupted injecting into the stratosphere large amount of gases and solid aerosol...

We revise the sunspot observations made by Galileo Galilei and Christoph Scheiner in the context of their controversy regarding the nature of sunspots. Those of their sunspot records not included in the current sunspot group database, used as a basis to calculate the sunspot group number, are analysed. Within the documentary sources consulted in th...

While the Sun is generally more eruptive during its maximum and declining phases, observational evidence shows certain cases of powerful solar eruptions during the quiet phase of solar activity. Occurring in the weak Solar Cycle 14 just after its minimum, the extreme space weather event in 1903 October–November is one of these cases. Here, we recon...

On September 3, 1880 a probable tornado caused significant damage in the city of Talavera de la Reina (Spain). In this work, we analyze the original description made by an observer of that time about this phenomenon and the meteorological conditions for that day. The potential formation of a tornado was possible according to our analysis. This woul...

Gaspar Melchor de Jovellanos is the major figure of the Age of Enlightenment in Spain. He observed the total lunar eclipse of 1794 February 14 from Gijón (north of Spain). Jovellanos described the moon color as “glowing iron.” It indicates that the stratosphere around 1794 seems to have been undisturbed volcanically as previous estimates indicate.

We present the sunspot observations made by Barnaba Oriani in 1778 and 1779 at the Brera Observatory (Milan, Italy). We have computed the number of sunspot groups and individual sunspots and extracted the positions of all individual sunspots recorded by Oriani. It must be highlighted that the observations made by Oriani in 1779 are not included in...

In this work, a landslide event that took place on January 1831 at the Pedregoso Mountains, Cabeza del Buey, SW Spain, is described. This landslide had not been documented to date and was only described in the local press. This event involved an estimated amount of dislodged material in the order of 104 m3. The amount of meteorological data is very...

Solar activity affects geophysical and heliophysical processes. Long-term changes in solar activity are closely related to climate change. Solar physicists and earth science researchers need longer observations of solar activity. Current continuous observations of solar activity are only about 400 years. Some scholars have compiled naked-eye observ...

The current COVID-19 pandemic is having detrimental consequences worldwide. The pandemic started to develop strongly by the end of January and beginning of February 2020, first in China with subsequent rapid spread to other countries with new epicenters of the outbreaks concentrated mainly within the 30-50 degrees North latitudinal band (e.g., Sout...

The current pandemic caused by the coronavirus SARS-CoV-2 is having negative health, social and economic consequences worldwide. In Europe, the pandemic started to develop strongly at the end of February and beginning of March 2020. It has subsequently spread over the continent, with special virulence in northern Italy and inland Spain. In this stu...

Rogation ceremonies are religious requests to God. Pro-pluvia rogations were celebrated during dry conditions to ask God for rain. In this work, we have recovered 37 pro-pluvia rogations from 14 documentary sources (e.g.,: ecclesiastical manuscripts, books, and different magazines and newspapers). All of the rogations were celebrated in Extremadura...

Newly discovered descriptions about the great aurora observed in March 1582 are presented in this work. These records were made by Portuguese observers from Lisbon. Both records described the aurora like a great fire in the northern part of the sky. It was observed during three consecutive nights, according to one of the sources. Thus, we present a...

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 accuracy of its results has been checked by using solar images provided by the Debrecen Photoheliographic Data (DPD). Due to its applicability in the studies of historical s...

While the Sun is generally more eruptive during its maximum and declining phases, observational evidence shows certain cases of powerful solar eruptions during the quiet phase of the solar activity. Occurring in the weak Solar Cycle 14 just after its minimum, the extreme space weather event in 1903 October -- November was one of these cases. Here,...

A global inventory of early instrumental meteorological measurements is compiled that comprises thousands of mostly nondigitized series, pointing to the potential of weather data rescue.

Sunspot observations, normally made with small telescopes during the last four centuries, should be considered a world heritage for many reasons including purely scientific aspects and other cultural and social reasons. Here, these aspects are briefly reviewed.

An analysis of the sunspot observations made by Hevelius during 1642–1645 is presented. These records are the only systematic sunspot observations just before the Maunder Minimum (MM). We have studied different phenomena meticulously recorded by Hevelius after translating the original Latin texts. We reevaluate the observations of sunspot groups by...

Some works have reported variations in direct solar irradiance at surface with solar activity one order of magnitude higher than changes in total solar irradiance at the top of the atmosphere (TSI) over the solar cycle. In the present study, daily pyrheliometer records from the Astronomical Observatory of Madrid for the period 1910–1929 have been r...