The Hodierna’s Nebulae

A Messier’s forerunner to the court of the early “Gattopardo”

In 1654, when Palermo was given to the press the treatise “De Systemate Orbis Cometici, Deque Admirandis Coeli Characteribus” Giovan Battista Hodierna, the real nebulae known you could count barely on the fingers of two hands: it was known since the ancient times, the double cluster in Perseus (h and c Persei), the cluster, the Coma cluster (Mel 111), the Praesepe (M44), the Pleiades (M45), M7, the Hyades (but no-one considered the Pleiades and Hyades as nebulae); in the historic era, were discovered in the Great Andromeda Nebula (M31, but few were aware of the existence of the book of Al-Sûfi, and the same applies to the rediscovery of Marius and Boulliau), and that in the Sword of Orion (M42). And you knew of the existence of the two Magellanic Clouds, although it was not easy for an astronomer european to observe them. If that book, fairly insignificant in its first part (on the theory of the comets Hodierna was far behind its time), it had been read with a minimum of attention by the astronomers of his time, but, even more, to those of the next century), the history of astronomy, in the three centuries that followed, would be told in a very different way.

Notes biographical and bibliographical

Giovan Battista Hodierna, interesting and unique figure and a pioneer of the emerging science, in which he explained his uncommon talent from the innumerable facets in the deep South of Sicily in the seventeenth century, was born in Ragusa on April 13, 1597. It was not Hodierna his real last name: the father, a modest craftsman, it was called Vito fourth place. The prefix “I” was added later by the same scientist, with obvious allusion to the hodie, which in Latin means “today”: and this is the testimony of an extraordinary enthusiasm for his “today”, and that is the century in which he lived and worked.

Of his juvenile studies, we know very little. But it is certain at a very early age his interest for astronomy: the age of just twenty, he obtained the authorization to use for his own observational activities the bell tower of the church of St. Nicholas (19) in Ragusa. Using rudimentary instruments, self-built, as he himself relates in his writings (20). From the observatory, he observed, between 1618 and 1619, the three famous comets whose appearance spurred the famous polemic that culminated in the Saggiatore of Galileo, and (21).

In 1622 he was ordained a priest in Syracuse. Of his early works, written in the period from ragusa, the most remarkable is The Nuncio of the Century, Crystal clear, written in 1628 and remained unpublished up to 1902, when it was published by A. Licitra (22). In NunzioHodierna extols the virtues of the time in which he lives, and man “oggidiano” (“oggidiano” comes from “today”, as Hodierna is derived from “hodie”), the new man, in contrast with the past that is viewed negatively and, in each case, as finally passed. This work, although important for the understanding of the thought of Hodierna, is the topic of philosophical rather than astronomical, and it does not seem the case to dwell on it; on its non-publication have made different assumptions (related both to uncertainties in theory and to political prudence (23)): the enthusiasm for the discoveries and the inventions, the great admiration for Galileo, and the philosophy that arose out of this, could be risky in those times and in that country where the Inquisition still exercised its oppressive influence; and in remembrance of Giordano Bruno burned yet (the condemnation of Galileo by the holy Office will take place on the other hand again a few years later, in 1633). In the Nuncio, he reported that on the 24th of June of that same year (1628), he received a telescope (a good Red) from that Rondonino of Rome (24).

In 1637, is the end of the period ragusa Hodierna, and begins to Palm of Montechiaro, the more fruitful and productive. In that year, we find him following in the footsteps of the brothers Carlo and Giulio Tomasi that, in the context of the Spanish policy of repopulation of the countryside and of agriculture, founded Palm. They provide a substantial prebend, sufficient to enable him to devote himself to his studies (25) and to produce, in the years that followed, numerous works, some of which are truly remarkable. In 1645 the bishop of Girgenti (Agrigento) for the appointment of the archpriest of Palma di Montechiaro (26).

Despite a few trips to Rome, Naples and Palermo, in which maintained close ties of friendship and mutual respect with several scholars of his time, such as Juan Caramuel y Lobckowitz, Athanasius Kircher, Gaspar Schott, M. A. Severino, the astronomer Francesco Fontana, and others, and in spite of the epistolary contacts with people of the calibre of Riccioli, Huygens, and Hevelius (27), staying in a small and isolated centre of Palma weighed like a cloak of lead on the scientist ragusa. The outburst of yearning that we can read on the De Admirandis of the Spectrum in Sole et Luna visis (written in 1656 in response to the questions sent to him from the cistercian Domenico Plato, professor of philosophy in the convent of Monferrato, in order to eclipse of the Sun of January of the same year) is testament to the sadness of a great intellect forced to make an unbearable isolation:

…Socium non habeo, vel amicum, aut propinquum, quo paululum sublevari possim. Mens mea praeceptor meus, et difficultates meas null communico…Et quia mens nunquam satiatur, persaepe in tenebras inexplicabiles incidit et implicatur. Ideo necessitudinem meam tibi communicate volui ac debui Friend tamquam optimo, ut qui inter speculandum light not indiges aliqua…precor humanitatem tuam, ut radium tuae claritatis impendas, et hasce ob oculos tenebras obvolutas resolvens, nebulas procul expellas, ne nimium inter hasce caligines obrutus depeream.

G. B. Hodierna died in Palma di Montechiaro, April 6, 1660.

Hodierna was more an encyclopedic than a specialist. His insatiable curiosity and his talent as a researcher led him to investigate every possible hidden secret of nature. He was attracted to botany and meteorology, anatomy, and entomology, from the “philosophy corpuscular” (he was a convinced atomista) and by the optics. He built himself a microscope and studied with extraordinary skill the eye of the fly and of other insects (The eye of the fly, 1644); it was probably the first to study and understand the nature and function of the fangs of vipers (Dentis in Viper-Virulent – Anothomia (sic!), 1644); he also studied the human eye (The Sun of the Microcosm, in 1644, and published his theories on the vision; he had interesting insights on the nature of the rainbow (Thaumantias Junonis Nuntia, etc, 1647), though his training in the field of optics, still too anchored to the theories of traditional, prevented him from coming to conclusions really innovative (28).

He inquired also about other sides of physics: with regard to the mechanics, for example, in his Archimede redivivo with the weight of the moment (Palermo, 1644) published The ” is a comment (29) of Galileo, and the tribute to the founder of the modern science represents not only the first publication ever of this work, which Galileo himself had left unpublished, but also the first publication of a work by the great Pisano after his death.

Although it was not devoid of contacts with the fringes important to the scientific community of the time, he took satisfaction that his extraordinary abilities inquiring of the secrets of nature they deserved. And, all the while enjoying discreet fame among his contemporaries, although his works were sought after his death by the likes of Oldenburg (the secretary of the Royal Society, who invited Newton to submit to the Society, his telescope and his new theory about light) and Boyle (30), he was virtually ignored by the scientific historiography for something like three centuries, until the passionate work of a few scholars from sicily, around the half of years ’80, it has thrown light on the undoubted value of an astronomer, adding an important paragraph in the history of astronomy. And indeed, apart from the enormous importance of works of the topic natural, like The eye of the Fly and the Dentis in Viper Virulent, the magnitude of Hodierna resides especially in his astronomical observations.

The astronomer

The archpriest of Palma and enjoyed considerable fame in the scientific community of his time, thanks to his studies on the four satellites of Jupiter discovered by Galileo: the Medicaeorum Ephemerides (31), of 1656, represent the first ephemeris, published in the satellites moons. And not less remarkable are his works on Saturn (32): he came more than anyone else, before Huygens, close to understand the real nature; he published a letter to the same Huygens on its observations (33), and it would have been the response, if the letter of the great Dutch scientist was lost in the maze of postal services of the time: never came in Italy, came back, and is still preserved in the Netherlands (34). Hodierna saw the ring, and he described the black (35), the empty space that separated him from the body of the planet. But, because of the modest quality of his telescope, he could not make the decisive step, and also, perhaps, to project it mentally in three dimensions.

The works which we have mentioned, together with his studies on comets, would be enough to ricavargli a place in history “minor” in astronomy. But there is another, the importance of which, probably precisely because of its characteristics, pioneering, was not understood by his contemporaries.

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