The codex kept at the Arnamagnean Institute, in Copenhagen, with the number 805 4º (København, Det Arnamagnaeanske Institut, Københavns Universitet, AM 805 4º), contains a combination of texts featuring legal and short historiographic... more
The codex kept at the Arnamagnean Institute, in Copenhagen, with the number 805 4º (København, Det Arnamagnaeanske Institut, Københavns Universitet, AM 805 4º), contains a combination of texts featuring legal and short historiographic pieces. In the latter we find a few astronomical references, among them a contemporary mention of the solar eclipse of June 3, 1239 containing what seems to be a reference to the solar corona. This reference could be added to the only other commonly accepted timed report of the corona from medieval times in the Annales Sangallenses regarding the total solar eclipse of the year AD968.
Research Interests: Eclipse and Solar Eclipse
In the context of the European Middle Ages as the period roughly covering from the 5th to the 15th centuries, the astronomical records are rarery found in scientific treatises. At least, not until the 15th century. A few surprinsing... more
In the context of the European Middle Ages as the period roughly covering from the 5th to the 15th centuries, the astronomical records are rarery found in scientific treatises. At least, not until the 15th century. A few surprinsing examples in which the observations were recorded in a particularly original way on stone are found. In this poster we will shortly review the only four cases in which this occurred in Europe.
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The aim of this paper is the study of the impact that the consideration of different physical properties as magnitude and spectral type of stars has on the geometric relations between Hipparcos2 and UCAC4. In this sense, the pairs of... more
The aim of this paper is the study of the impact that the consideration of different physical properties as magnitude and spectral type of stars has on the geometric relations between Hipparcos2 and UCAC4. In this sense, the pairs of residuals Δα* and Δδ can be considered as functions of (α, δ, r) and for each fixed r, we can fit a vector field on the sphere from which to obtain its components in the VSH basis. The same can be done by grouping the stars considering their magnitudes, spectral types (or mixing them) and then studying the variations in the mentioned geometry. We must not forget that Δα* and Δδ are numerical random variables whose regression on the magnitude m, for example, can be estimated. The results will be computed taking into account r as well as the physical mentioned properties. So, we avoid the assumption that the harmonic coefficients depend only on m.
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One of the important challenges that Gaia imposes on the Astrometric Catalogs, is a careful study in everything affected by parallax. A particularly important case is the necessary linkage Gaia - HCRF - ICRF2, which require methods of... more
One of the important challenges that Gaia imposes on the Astrometric Catalogs, is a careful study in everything affected by parallax. A particularly important case is the necessary linkage Gaia - HCRF - ICRF2, which require methods of analysis that are accurate enough so that the provided results are at the same precision level as the work data.
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Research Interests:
Existing research dealing with astronomical observations from medieval Europe have extensively covered topics such as solar and lunar eclipses and sightings of comets and meteors, but no compilation of occultations of planets by the Moon... more
Existing research dealing with astronomical observations from medieval Europe have extensively covered topics such as solar and lunar eclipses and sightings of comets and meteors, but no compilation of occultations of planets by the Moon has been carried out and, till now, the data have remained scattered in different publications. The main reasons for this are the small number of observations that has reached us, their limited use for calculation of parameters associated with the rotation of the Earth, and the fact that between the fifth and fifteenth centuries, the period that we consider, almost none of these observations were made scientifically, since they usually appear in narrative texts, be they chronicles or annals. Our purpose is to make a compilation of these phenomena, trying to shed light on some of the most controversial observations after examining them in their historical context. We will examine European sources, but, occasionally, we will also consider reports from...
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The lack of astronomical observations from medieval and early modern Spanish sources is a constant in the records of solar eclipses, meteors, and other celestial phenomena. This may be partially explained by the absence of a documentary... more
The lack of astronomical observations from medieval and early modern Spanish sources is a constant in the records of solar eclipses, meteors, and other celestial phenomena. This may be partially explained by the absence of a documentary corpus similar to the Monumenta Germaniae Historica, for example, that scholars may use for conducting a systematic search of such records; the problems increase by the presence of four different vernacular languages in the peninsula: Castilian, Catalan, Basque, and Galician, together with some other minority languages, to which Latin and Arabic must be added for historical research purposes. Currently, scientific literature records few medieval Spanish astronomical accounts, and most of them are contained in wider Arab surveys or they come from the best-known annals and chronicles. Our article intends to fill this gap partially in the issue of meteoritic activity. We present a survey of meteors, bolides, and meteor storms observed in Spain in the ei...
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It is a long time since the last comprehensive compilation of meteoric observations from medieval European sources was published. Since then, the advances in information technology, search engines and, above all, the emergence and... more
It is a long time since the last comprehensive compilation of meteoric observations from medieval European sources was published. Since then, the advances in information technology, search engines and, above all, the emergence and development of the Internet have facilitated the access to and search for these records for scholars, making their work easier and even avoiding the need to go to libraries that keep the documents. In this paper, we have significantly enlarged the list of reports of medieval European meteoric events, using mainly the current classical sources and also other local documents previously not considered by the authors that have dealt with this issue.
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The eclipse of a.d. 1239 June 3 was observed at no less than 10 sites in Europe, but the one from a.d. 1354 September 17 was observed only from two European sites. In this paper, we present several new references for the a.d. 1239 and... more
The eclipse of a.d. 1239 June 3 was observed at no less than 10 sites in Europe, but the one from a.d. 1354 September 17 was observed only from two European sites. In this paper, we present several new references for the a.d. 1239 and a.d. 1354 solar eclipses, most of them from unpublished Spanish documents. In particular, we study three records engraved on stones whose existence was not known until recently. Such records are very rare in the rest of Europe. The study of ancient eclipses has proven to be useful for obtaining some astronomical data of interest to modern astronomy. In particular, the analysis of these eclipses may be useful for determining a range of ΔT for the epochs.
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In 2008, after 13 years of preparation, the Generalitat of Catalunya finished the publication of the 10 volumes of the Dietaris de la Generalitat de Catalunya. The Dietaris, as well as a closely related source, the llibre de Jornades... more
In 2008, after 13 years of preparation, the Generalitat of Catalunya finished the publication of the 10 volumes of the Dietaris de la Generalitat de Catalunya. The Dietaris, as well as a closely related source, the llibre de Jornades 1411/1484 de Jaume Safont, cover the period of 1411 to 1539. In this article, we examine astronomical references contained in these two sources, and place them in their historical context. Our main focus lies on astronomical phenomena that have not previously been published in the astronomical literature. In fact, relatively few astronomical records are accessible in Spanish medieval and early modern history, and our paper intends to fill this gap partially.
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The main aim of this paper is the construction of a set of computational tools in order to improve the management of large expansions used in celestial mechanics. This package involves an iterative algorithm to develop the inverse of the... more
The main aim of this paper is the construction of a set of computational tools in order to improve the management of large expansions used in celestial mechanics. This package involves an iterative algorithm to develop the inverse of the distance according to an appropriate set ...
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From 1998, the International Astronomical Union (IAU) adopted a new Celestial Reference System: the International Celestial Reference System (ICRS). The first optical materialization was the Hipparcos catalogue, defining the Hipparcos... more
From 1998, the International Astronomical Union (IAU) adopted a new Celestial Reference System: the International Celestial Reference System (ICRS). The first optical materialization was the Hipparcos catalogue, defining the Hipparcos Celestial Reference Frame (HCRF). The compilation of subsequent radio sources catalogues culminated in the current representation of the ICRF, the ICRF2 catalogue that is not sufficiently dense to cover all astrometrical purposes. Linking Hipparcos and ICRF2 is essential to uniformize the reference regardless of whether it is visible (HCRF) or not (ICRF). Many working groups provide their own complementary catalogs, some of whose sources are also in the ICRF2, with different reduction processes for positions. The point is that they provide information in more than one reference for a small number of objects. Some of these projects have been used by us to study the Hipparcos-ICRF2 differences: a certain number of couples of catalogs can be interrelated ...