Revolutionary in conception & richly symbolic, a very scarce late 17th Century celestial chart by German astronomer Erhard Weigel

Speculum Uranico-Europaeum. Astroscopium Orbi Europaeo Sacrum Erhardi Weigelij Mathem. Prof. P. Jena

Imprint [lr]: Sumptibus Autoris. / Sculp. Johann Dürr[in]

Copperplate engraving. Traces of original folds, now flattened. Narrow bottom margin as issued, with small extension at lower right margin, where map appears to have been originally bound in to book. Light verso reinforcement of top and bottom sheet edges. Fine modern hand colour.

This exceedingly scarce and highly unusual 17th Century celestial chart was formulated and designed by the influential German philosopher, astronomer and mathematician, Erhard Weigel [1625-1699].

Weigel is a notable and influential figure in 17th Century mathematics and astronomy, mainly as a result of his long-standing position as a prominent teacher and lecturer who greatly popularized the study of maths,  science and astronomy. He held the position of Professor of Mathematics at the University of Jena from 1653 until the time of his death in 1699. Several notable German mathematicians & astronomers studied under him at Jena and were considerably influenced by his teachings, amongst the best known being Gottfried Wilhelm von Leibniz [1646-1716] and Georg Christian Eimmart [1638-1705].

However Weigel was more than just a teacher, as this fascinating, revolutionary and innovative celestial chart clearly demonstrates. The chart, which appears to have been first published in 1661 (though numerous examples are catalogued with a date of 1688 – there were seemingly subsequent editions in 1681 & 1688 (interestingly the same year in which Weigel was appointed an Imperial advisor)). The map is closely associated with a promotional pamphlet of that latter date and an instructional celestial globe which was produced in the last year of Weigel’s life in 1699. A fine example of this globe is preserved in the collections of the National Maritime Museum at Greenwich.

Weigel’s celestial chart and globe are the focus of an excellent blog post by Michael Kay in Feb 2012, which provides a wealth of detail and information. In essence Weigel sought to formulate, propagate and promote an entirely new and revolutionary map of the Heavens, one that replaced the existing panoply of pagan and classical constellations with what he considered to be a far more rational contemporary system based upon the heraldic arms & devices of the nation states and principalities of 17th Century Europe, as well as of its principal hierarchies and social classes. The European section is here represented in the form of a panoramic perspective of the Milky Way, dotted with these newly emblazoned constellations, and symbolically placed within the all-enveloping winged embrace of the double-headed Eagle of the Holy Roman Empire, its claws clasping the emblems of power, the sceptre and sword. Equally symbolically the Eagle hovers in the celestial firmament above a globe of the world upon which is imprinted a detailed map of Northern Europe, extending from the coasts of East Anglia in the West to the farthest shores of the Caspian Sea, Persia & Tartary in the East.

Weigel’s 1688 pamphlet promoted the idea of a new scientific curriculum in schools and universities which would utilize the proposed new globes for instructional purposes. Interestingly Weigel’s 1699 Greenwich globe differs significantly from other contemporary globes insofar as the newly proposed “emblazoned” constellations are shown superimposed upon their traditional precursors, and perhaps most unusually, are also modelled in relief, standing proud of the globe surface.

Born of Protestant parents in Bavaria in 1625, Weigel was forced to flee his home town due to the depradations of Catholic troops during the Thirty Years War. Much of his initial education during the 1640’s took place in Halle, where he came under the tutelage of astronomer Bartholomaeus Schimpfer. He continued his studies at the University of Leipzig where he gained a Doctorate in Philosophy in 1650. In July 1653 he was offered the Professorship of Mathematics at Jena, in September of the same year marrying wealthy widow, Elisabeth Hartmann. He was also closely involved in moves to reform the Julian Calendar which, despite the introduction of the Gregorian calendar in 1582, was still used, almost without exception, amongst the Protestant states of Germany.  As Michael Kay notes: In the second half of the seventeenth century Weigel campaigned tirelessly to persuade the protestant states to finally adopt the new calendar. His efforts were rewarded shortly after his death as the German and Scandinavian protestant states finally decided to introduce the reformed calendar at the beginning of 1700. With further modification, the revised Gregorian calendar was introduced by the rest of Europe in the 1750’s. Weigel’s catalogue of works on mathematics and astronomy is extensive, but one particular work, first published in 1661, appears to provide the formative ideas & intellectual foundations for this chart and the later 1699 globe. Indeed the book’s title would suggest that the chart was originally planned as an illustrated plate for this specific volume (though it frequently appears to be lacking from many institutional examples of this edition)

The full title of the work is as follows:

Speculum Uranicum Aquilae Romanae Sacrum, Das ist, Him[m]elsSpiegel : Darinnen Ausser denen ordentlichen, auch die ungewöhnlichen Erscheinungen des Himmels mit gebührenden Anführungen abgebildet, Vornehmlich aber Der im Gestirne des Adlers jüngsthin entstandene Comet, Nebenst einer neuen Himmels-Charte, unter dem Adler des H. Römischen Reiches, dargestellet wird

Roughly translated:

The Heavenly Mirror of the Imperial Roman Eagle, that is Himmelsspiegel: wherein as well the ordinary also the unusual phenomena of the Heavens are displayed with proper citations, but especially the recently appeared Comet in the constellation of the Eagle, and including a new Chart of the Heavens in the form of the Eagle of the Holy Roman Empire.

The comet referenced in the title of the work is shown in a beautifully engraved frontispiece to the volume (also engraved by Johann Dürr) its burning nucleus and fiery tail flying high over the University College buildings & astronomical observatory of Weigel’s Jena, clearly visible just above the head of the eagle of the constellation Aquila. A comet is also shown on the chart itself, on the far right, in the background skies, but adjacent to Weigel’s newly formulated constellation of the Imperial Eagle (of the Holy Roman Empire) on the chart of the Milky Way.

The comet was also observed by fellow astronomer Johannes Hevelius in Danzig in February and March of 1661. In the Spring of 2002, the Smithsonian Astrophysical Observatory at Cambridge, MA identified the Comet Ikeya-Zhang, visible in the night skies in April of that year, as this same (returning) comet of 1661.

The dedicatory foreword to Weigel’s 1661 Speculum Uranicum is addressed to the Holy Roman Emperor, Leopold I [1658-1705]. An awkward bookish monarch, deeply religious in his devotions and heavily influenced by his early Jesuit teachers, he was readily conversant in the arts and sciences, and especially interested in science, astrology and alchemy.

For Weigel, though a Protestant by religion, the appearance of the 1661 comet in the constellation Aquila offered a highly auspicious portent. Much is made by Weigel in his foreword of the comet’s bright glow and its reflected luminescence within the constellation Aquila. Indeed Michael Kay has suggested in his blog that Weigel’s aim was probably to do away with the superstitious pagan imagery of the past, particularly the naked figures of earlier celestial cartographers, “the last vestiges of an unenlightend age”, which offended his own Protestant sensibilities. The 1661 work clearly acknowledges the powerful and enduring symbolic grip of the Imperial Eagle on the contemporary German psyche, despite the disastrous recent depradations of the Thirty Years War and the enduring geopolitical patchwork of Central European states & principalities with widely divergent political affiliations & religious allegiances which characterized contemporary Germany and the Hapsburg lands of the Holy Roman Empire. Weigel’s implication is perhaps that the over-arching political influence and authority of an enlightened Holy Roman Emperor might in fact offer the best opportunity for enduring German (& European) peace, prosperity and patronage in this uncertain post-war period. The highly obsequious tone of his dedication to Emperor Leopold in the Speculum Uranicum might suggest that this indeed was at the forefront of his own mind. Indeed, eventually, in 1688 he was appointed a special Imperial advisor (kaiserlicher Rat). Interestingly in this same dedicatory foreword, Weigel highlights the position of the Eagle as the symbolic King of birds, holding legendary sway over all creatures of the air.

This chart and his subsequent globe offered an opportunity to formulate a rationally ordered ideal of an entirely secular European hierarchy defined exclusively in heraldic terms, and one that might be displayed (literally) in mirror image for posterity in a radically new cartography of the Stars and constellations: the Heavens and Earth symbolically conjoined under the outspread wings and encompassing embrace of the (Imperial) Eagle.

Unfortunately, despite many powerful backers and patrons, Weigel’s new celestial map never caught on. Many critics highlighted the difficulties of implementing these radical reforms and changes on an international basis.

Whilst support emerged from many of his students, including von Leibniz, the resistance and inertia of the European scientific community and the perhaps comfortable familiarity and traditional sentimental attachment of many astronomers to existing celestial models meant that the idea itself died with Weigel himself at the end of the 17th Century.

The chart itself offers many new and interesting heraldic blazons of the European nations. France is the traditional fleur de lys (top left and in upper polar calotte), Denmark is an elephant (top right and in the upper polar calotte) replacing the form of the Great Bear constellation, Ursus Major. England is represented by a celtic Harp top centre; the Papacy is represented by a tiered papal tiara (left); Weigel’s native Bavaria appears as an orb upper left;  Brandenburg now adopts the form of the constellation of Aquila; Poland is a horseman (as portrayed on the coat of arms of Lithuania) adjacent to the English harp;  the Golden Fleece (toison d’or) of Spain and towers of Castile appear top right, close to the Triple Crowns of Sweden and, in the lower right, a the Lion of St.Mark (Venice).  Adjacent to Venice, the bejewelled ring of Florence, a Genoese cross, a Maltese cross, the crescent moon of Turkey, and in lower left, the distinctive form of a Tartar owl.

In all a most rare and unusual 17th Century celestial chart,  marking one of the last systematic attempts by any  European astronomer to fully redesign the existing map of the celestial firmament.

References:

Museo Galileo Website: Erhard Weigel’s Astroscopium Orbi Europaeo Sacrum (dated 1688)

National Maritime Museum – Weigel Instructional Globe, 1699

Elly Dekker: Globes at Greenwich (OUP, 1999);

Werner Horn: Die Alten Globen der Forschungbibliothek und des Schlossmuseums Gotha (Gotha, 1976)

Werner Horn: Der Heraldische Himmelsglobus des Erhard Weigel (in: Der Globusfreund, Nr 8, 1959)

Nick Kanas: Star Maps: History, Artistry & Cartography (Praxis Publishing Ltd, 2007)