Silva Rerum | 07.09.2015 Johannes Hevelius (1611–87), astronomer from Gdańsk, was one of the most prominent scholars in seventeenth-century Poland, celebrated in European scientific circles and appreciated by royalty. Though no ground-breaking theory or discovery bears his name, he remains one of the brightest stars in the firmament of the old Commonwealth’s science.
The future astronomer was born on 28 January 1611 the eldest son of Abraham and Cordula née Hecker. He belonged to a wealthy family of brewers and merchants. Surviving documents contain numerous variations of his family name—the astronomer himself used the Latinised form ‘Hevelius’ since he became a student.
His education began in 1618 at the Academic Gymnasium in Gdańsk, an institution which prepared the youth of the city over the Motława for further studies, typically at one of many renowned universities in Germany or the Netherlands. He also took private instruction from Peter Krüger (1580–1639), a mathematician and astronomer who taught at the gymnasium. Krüger infused Hevelius with an interest in exact sciences; many years later, at the height of his fame, the student retained fond memories of his teacher.
It is said that Hevelius spent a while in an unidentified township of Gondetsch, learning Polish. The language proved of great use in Gdańsk, where much business was conducted with the rest of the Commonwealth. Polish was also taught—as a foreign language—at the Academic Gymnasium in Gdańsk.
The future astronomer enrolled at Leiden in 1630, initially intending to learn cameralism (a branch of knowledge combining law and economy, very useful for a wealthy burgher with an interest in public or economic affairs) rather than exact sciences. He never finished his studies; instead, he took a scientific tour of Europe. He reached London as early as 1631 and then traversed France until 1634. During his travels, he met the Jesuit polymath Athanasius Kircher (1602–80), one of the most versatile scholars of the era, and many others. In his later years, Hevelius exchanged letters with Kircher.
His father prevented Hevelius from taking a trip to Italy, ordering his son to return home. In Gdańsk, the young scholar embarked on a career befitting his origins—he joined the guild of brewers, eventually becoming a councillor for Old Gdańsk and taking up other public roles. In 1635 he married Katharina née Rebeschke (1613–62). After her death, he wedded Elisabeth née Koopmann (1647–93).
Later in his life, Hevelius ascribed his return to academic work to master Krüger. On his deathbed, the old teacher is said to have implored his student to keep faith in astronomy and conduct observations during the impending eclipse of the sun. Hevelius conceded and remained faithful to Urania until his last days.
The scholarly endeavours of Hevelius are best perceived through a chronological breakdown of his most significant works and publications. The Gdańsk astronomer entered the academic scene with a bang—already his first book, Selenographia, sive Lunae descriptio (Selenography, or, a Description of the Moon, published in 1647 in Gdańsk, like all his works) brought him fame and recognition. The work consisted of a detailed description of the results of study and observation of Earth’s satellite. Included were, for instance, explications of the Moon’s movement around Earth, the transitions between phases (with a long series of detailed images), as well as mountain ranges on the surface of the satellite—observed by Galileo, confirmed by Hevelius. To facilitate the description, he assigned names derived from ancient geography to objects on the Moon, placing Sicily, the Mediterranean Sea, and Mount Sinai on its surface. (Against common conviction, however, he did not believe the Moon to be inhabited.) The names suggested by the Gdańsk astronomer were not retained. The maps included in the work offered the first explication of the Moon’s libration—the oscillation of the satellite over the course of its movement around Earth, which is why we see not a half, but ca. 59 percent of the Moon’s surface. Hevelius also details his observations of other planets, devoting a longer passage to the then-recent discovery of sunspots. Selenography was dedicated to King Władysław IV, whom the astronomer honoured by naming a group of stars in the Aquarius constellation Ladislaus’ Stars. The book was well-received in academic circles and ensured the young scholar’s worldwide recognition.
Another major topic Hevelius chose to tackle were comets. The results of his observations of these unpredictable (in the astronomer’s times) celestial bodies was a series of shorter works devoted to particular comets capped by a summation of this line of research in the sizeable volume entitled Cometographia (Cometography, 1668). Neither nature nor the heavens made Hevelius’ labour on this volume easy—two comets appeared on the skies in unprecedented clarity toward the end of 1664 and in the Spring of 1665, while the book was already being printed. The astronomer was thus prompted to halt the work on the larger study to describe current occurrences in smaller treatises. In these works, he sometimes cites particular pages from the as yet unavailable Cometography. The view Hevelius espoused with regard to comets differed significantly from the common convictions—he believed they emerged from the miasma of planets and were shaped like a discus. The Gdańsk scholar was not the only one to err in that regard, and the nature of comets remained a mystery to astronomers for many years further.
Hevelius summed up a longer period of research in the two-volume Machina coelestis (The Machinery of the Heavens, vol. 1 published in 1673, vol. 2 in 1679). The first volume is by far the best known of the two; it includes a detailed description of the scholar’s astronomical instruments. Magnificent etchings depict various tools for measurement and telescopes, the structure of the observatory located on top of tenement houses in Gdańsk, and also the astronomer himself and his helpers (including his second wife, Elisabeth) at work. These images are often reproduced in publications devoted to Hevelius and have even appeared as decorative motifs in works that make no mention of the astronomer at all. The second volume of The machinery of the heavens includes descriptions of observations of various heavenly bodies conducted over many years of study.
Throughout his life, Hevelius collected materials for a new catalogue of the stars, which he failed to publish before his death. The work was completed by Elisabeth, the astronomer’s widow. At her behest, two books appeared in 1690—Prodromus astronomiae (Introduction to Astronomy) and Firmamentum Sobiescianum, sive Uranographia (Sobieski’s Firmament, or, Uranography). The Introduction to astronomy is Hevelius’ magnum opus—a catalogue indicating the position of nearly two thousand fixed stars. The accompanying Sobieski’s Firmament is, as the title indicates, an atlas of the heavens dedicated to King Jan III, including formidable illustrations of constellations on both hemispheres. These books constitute the apex of Hevelius’ research work.
Outside of the big volumes, the astronomer also published numerous smaller works devoted to questions such as the transit of Mercury and Venus or an (erroneous) explication of the shape of Saturn. Since 1662 the Gdańsk scholar published his books by himself. All his volumes are marked by high-quality editing and magnificent illustrations, prepared in the author’s own hand or under his direction.
Hevelius conducted an extensive scholarly correspondence. Among his correspondents were other scholars as well as men of means, figures of smaller or greater renown. The astronomer exchanged letters with such luminaries of seventeenth-century science as French astronomer Ismaël Boulliau (1605–94), Dutch scholar Christiaan Huygens (1629–95), or Jesuit mathematician Adam Adamandy Kochański (1631–1700). His main contact in England was Henry Oldenburg (ca. 1618–77), a long-time secretary of the Royal Society; he also sent letters to such figures as Pierre des Noyers (1606–93), secretary to Queen Marie Louise, at the court in Warsaw. Hoping to publish his correspondence, the astronomer collected both the letters he received and copies or rough drafts of those he sent himself, amounting to almost three thousand documents. Hevelius could not realise his intention during his lifetime, and his inheritors resigned from fulfilling it, discarding the collected correspondence instead. The letters were moved to Paris, where they now reside at the library of the Paris Observatory (original letters) and at the French National Library (copies of letters prepared for publication). The designs of Hevelius have only recently been implemented—his correspondence is due for publication within the next few years.
The Gdańsk astronomer’s standing in the scientific community is testified to by his induction to the English Royal Society in 1664. His achievements also received commendation from royalty. Hevelius enjoyed positive relations with members of the Polish Vasa dynasty—as already mentioned, he dedicated Selenography to Władysław IV. He also treated the King to a polemoscope of his invention—or, to use a more modern term, periscope—as a useful tool during military operations. The astronomer also benefited from the grace of Jan Kazimierz, who paid a visit to the scholar’s observatory in 1659. Since 1663 Hevelius also received an (irregular) scholarship from the King of France Louis XIV, the dedicatee of the first part of The Machinery of the Heavens.
Hevelius came into contact with the milieu of Jan Sobieski already before the latter’s election, when the future king sought to acquire a telescope. After his coronation, Jan III granted the astronomer a yearly salary and exempted his breweries from taxation. Hevelius dedicated the second part of The Machinery of the Heavens to the King, along with the posthumous Introduction to Astronomy and Sobieski’s Firmament. After the Battle of Vienna, the astronomer outlined a constellation he named Sobieski’s Shield (Scutum Sobiescianum, now referred to as the Shield) in honour of Jan III.
Since the beginning of his scientific career, Hevelius was a proponent of the Copernican heliocentric model. While the central placement of the Sun was not of primary concern to him, he never put it in any doubt and rejected the conception of the structure of the universe proposed by Danish astronomer Tycho Brahe (1546–1601), who thought that the immobile Earth was circled by the Sun, which, in turn, was encircled by the other planets. During the seventeenth century, Brahe’s model constituted the main alternative to the heliocentric model. Though the Copernican conception of the structure of the universe rose in popularity, it continued to face opposition—both scientific (pointing out its incompatibility with the entire previous astronomy and absence of proof) and non-scientific (stressing its incongruity with the Holy Scripture and common sense, which certifies the visible movement of the Sun across the sky). Hevelius also underlined the significance of the mathematical apparatus for astronomical study proposed by the astronomer from Toruń.
Though Hevelius enjoyed considerable renown among his contemporaries, he was indeed the last astronomer of the passing era of observation by the naked eye. In spite of his use of telescopes—already his Selenography includes detailed descriptions of the Moon and other celestial bodies—he never employed them in establishing the positions of stars for his catalogue. That work was owed to antiquated instruments equipped with sights, designed for use with the naked eye. Hevelius’ unwillingness to use telescopes for his catalogue is understandable—at the time when he set out compiling it, such instruments were not yet accurate enough to permit precise definition of the placement of stars. For this reason, though, the life-work of the Gdańsk astronomer became a part of a bygone era in astronomy.
The fact that Hevelius did not use telescopes for establishing the position of stars occasioned the most significant dispute he took part in. When the first part of The Machinery of the Heavens came out, English scholars—astronomer John Flamsteed (1646–1719) and mathematician and physician Robert Hooke (1635–1703)—questioned the accuracy of the Gdańsk scientist’s observations.
Hooke’s critique was particularly vile. The dispute was apparently settled by Edmund Halley (1656–1742), who visited Gdańsk in 1679 and conducted observations using the instruments provided by Hevelius and his own telescopes with sights. Of note is the fact that, contrary to common opinion, Halley’s visit was not orchestrated by the Royal Society with a view to settling the dispute between the scholars, even though that was its eventual result. The English astronomer decided that Hevelius’ tools provided indications consistent with those offered by the newer instruments and ensured sufficient precision. Though the Gdańsk scholar was very pleased with that verdict, history would side with his opponents—astronomy’s future lay in telescopes.
No discussion of the life and activities of Hevelius is complete without mention of the sad event that befell him in his final years. On the night of 26–27 September 1679 a fire ravaged his homes, brewery, observatory, and printing shop. The treasured instruments of observation the astronomer had proudly amassed for many years were gone. Luckily, his manuscripts survived—both research notes and the collected scientific correspondence. Hevelius received aid from the likes of Jan III, who ordered that a sumptuous bonus be added to his regular salary. The ageing astronomer did not shirk from continuing his scientific endeavours, but he failed to reconstruct his observatory before his demise. He died on the day of his seventy-sixth birthday, 28 January 1687.
The astronomer’s inheritors were not interested in continuing his scientific pursuits. The scholar’s correspondence and observatory notes were acquired by French astronomer Joseph-Nicolas Delisle (1688–1768) in 1725 and brought to Paris. One of Hevelius’ printing plates for Selenography came to be used as a platter; the rest were sent away for melting. The most important remembrances in the astronomer’s native town are copies of his books—formidably bound, with hand-coloured illustrations—which he gifted to the Library of the Town Council (now the Gdańsk library of the Polish Academy of Sciences); a portrait of Hevelius by Daniel Schultz (1615–83) found in the same library; and a diploma certifying his induction to the Royal Society, stored in the National Archive in Gdańsk.
Hevelius’ nationality may pose fewer questions than that of Copernicus—a welcome state of affairs, to say the least—but several observations have to be made in this respect, as well. Hevelius was a German burgher in a German-speaking city. As already stated, he learned Polish as a foreign language. However, as the city belonged to a multinational Commonwealth, the Gdańsk astronomer could boast of being a citizen of the Polish world—civis orbis Poloni. Since we can no longer ask our subject about his national identification, we should leave it at that, remembering that dressing Hevelius up as a Polish nobleman is as deluded as crossing him out from the history of Polish science in the seventeenth century.
Suggested readings:
The latest full biography of Hevelius in Polish is Przemysław Rybka’s Heweliusz (Warsaw 1989). It discusses the entire life of the Gdańsk astronomer, but due to its age it tends to diverge from the later works about the scholar. Daniel Wierzbicki’s “Żywot i działalność Jana Heweliusza, astronoma polskiego. Skreślone ku uczczeniu 200-letniej rocznicy jego śmierci” (The Life and Activities of Johannes Hevelius, Polish Astronomer, Compiled to Commemorate the 200th Anniversary of His Death, Pamiętnik Akademii Umiejętności w Krakowie, Departments of Philology and History-Philosophy, vol. 7, 1889, p. 22–78) remains a captivating read in spite of being even farther away from the most recent findings.
Readers interested in Hevelius are advised to consult the following volumes published in conjunction with the 400th anniversary of the astronomer’s birth, which contain articles devoted to various questions related to Hevelius’ career and the people he met:
– Richard L. Kremer and Jarosław Włodarczyk, eds., Johannes Hevelius and His World. Astronomer, Cartographer, Philosopher and Correspondent, Studia Copernicana series, vol. 44 (Warszawa 2013);
– Maria Pelczar and Jarosław Włodarczyk, eds., Jan Heweliusz (Radom 2011; the volume includes a bibliography of Hevelius’ works, compiled by Maria Otto);
– Maria Mendel and Józef Włodarski, eds., Jan Heweliusz i kultura heweliuszowska. Utilitas et delectatio (Gdańsk 2013);
– Marian Turek, ed., Johannes Hevelius and His Gdańsk (Gdańsk 2013).
The latest and most detailed biography of Hevelius is ‘Hevelius et son temps’ by Chantal Grell, included in the first volume of the Gdańsk astronomer’s correspondence—Chantal Grell, ed., Correspondance de Johannes Hevelius. Tome I: Prolégomènes critiques (Turnhout 2014). The same volume also includes bibliographies of works devoted to the scholar.
Translation: Antoni Górny
