A Sunderland Collection Highlight

Bayer's Uranometria

Introduction

For this featured collection highlight, we invite you to join us for a spot of seventeenth century stargazing as we share a seminal work that combines ancient celestial lore and the latest astronomical discoveries: Johann Bayer’s Uranometria Omnium Asterismorum Continens Schemata (1639).

Black and white engraved title page for Bayer's Uranometria. This title page includes Latin and Greek text, and allegorical illustrations. Engraving of the standing figures of Atlas and Hercules on pedestals; to the sides are the gods Apollo (the sun), Cybele, and Diana (the moon) at head; a Capricorn and a panoramic view of Augsburg at foot..

For millennia, star maps have been essential tools for exploration and astronomical study. Whether presented on globes, within scientific books, atlases, or simply as standalone charts, these celestial guides were crucial for helping astronomers and navigators understand and explore our world.

The earliest printed European maps of the night skies were produced in 1515 by Albrecht Dürer, Johann Stabius, and Konrad Heinfogel. Having created a woodcut terrestrial map of the world as a sphere (also 1515), Dürer and Stabius naturally followed up with its celestial counterpart.

Black and white early wood cut celestial map of the Northern Hemisphere, surrounded by found portraits of early astronomers. Gothic lettering title.
Black and white woodcut star chart showing the southern hemisphere.

Images courtesy of The Met, Public Domain - Harris Brisbane Dick Fund, 1951

The sheet depicting the northern hemisphere also featured the likenesses of early astronomers: Aratus, Ptolemy, Marcus Manilius, and Azophi Arabus (ʿAbd al-Raḥmān ibn ʿUmar al-Ṣūfī).

These two hemispherical charts were further developed by Petrus Apianus’ in his illustrious instrument work in Astronomicum Caesarium (1540), and in the 1541 star maps of Transylvanian mapmaker and theologian Johannes Honter (1498-1549).

The constellations depicted in Honter's charts used a radical new perspective of the stars from Earth in a concave projection, and rather charmingly act as a historical record of contemporary dress.

©The Sunderland Collection

First published in 1603, Uranometria was one of the grandest and most influential celestial achievements of the period. Renowned for its cartographic precision and artistic beauty, this star atlas was a comprehensive, pre-telescopic vision of the heavens - it is the first star atlas to plot the complete celestial sphere, with over 1,200 stars!

Who was Johann Bayer?

Bayer (1572-1625) was born in Rain, Bavaria in southeast Germany. He studied law and philosophy at the famous University of Inglostadt in 1592, and later worked as a lawyer and the official legal advisor for Augsburg’s city council in 1612. Little else is known about Bayer's life, in part because of the fact there were several eminent figures with the same name.

As well as his career in law, and a keen interest in mathematics and archaeology, it was the field of astronomy that was his passion. Through careful study, he taught himself how to observe, record and categorise the stars in the night sky - this later became his claim to fame.

Classical Influence, Modern Data

Uranometria splendidly compiles Bayer's astute observations of the cosmos. For the first time, an astronomer merged the precise stellar positions with artistic rendering of the constellations. The work does not entertain conversations around the position of the Earth and other celestial bodies within the universe - a hot topic at the time!

The most prominent influences for the work were:

The al-Ṣūfī manuscripts, Kitāb ṣuwar al-kawākib al-thābita [Book of the Images of the Fixed Stars] (c.1000) by Persian astronomer ʿAbd al-Raḥmān ibn ʿUmar al-Ṣūfī, who was known in Europe as Azophi Arabus (903-986 BCE)

Image: Bedouin Constellation in the form of a camel alongside the Classical Constellation of Andromeda. ©Bodleian Libraries, University of Oxford

The work also draws heavily on Regiomontanus' printed edition of Ptolemy’s Almagest (1496), and ‘De le Stella Fisse’ [‘On Fixed Stars] in 1540 by Alessandro Piccolomini (c1559-1620). One of the issues with Piccolomini’s work, however, was that it did not include a coordinate system meaning that readers could not easily or accurately locate individual stars.

Image: Piccolomini's De le Stelle Fisse (1540), showing plate 35 the constellation Orion. Courtesy of The Linda Hall Library of Science, Engineering & Technology.


Uranometria also includes a vast amount of scientific data from Tycho Brahe’s star catalogue of 1602 which plotted the positions of 1,005 stars. Bayer is also said to have been in possession of a manuscript copy of Brahe’s observations of the northern hemisphere as a guide prior to its formal publication.

It is thought that Bayer may have also accessed this information through the globes of Jodocus Hondius and Willem Janszoon Blaeu, or the astronomical tables of Johannes Kepler.

The illustrations of the personified and anthropomorphised constellations are by the Dutch painter Jacob de Gheyn II (1565-1629). De Ghyen’s drawings were highly accomplished in an artistic sense, but they were not scientifically accurate. The exquisitely engraved plates were realised by the German engraver Alexander Mair (c.1559–c.1620).

The Northern Hemisphere

Uranometria painstakingly illustrates the 48 constellations described by Claudius Ptolemy in the ‘Almagest’. The fixed positions of these stars in the northern hemisphere has been based on the work of Danish astronomer Brahe.

The Ptolemaic constellations were: Andromeda, Aquarius, Aquila, Ara, Argo Navis, Aries, Auriga, Boötes, Cancer, Canis Major, Canis Minor, Capricornus, Cassiopeia, Centaurus, Cepheus, Cetus, Corona Australis, Corona Borealis, Corvus, Crater, Cygnus, Delphinus, Draco, Equus Minor, Eridanus, Gemini, Hercules, Hydra, Leo, Lepus, Libra, Lupus, Ophiuchus, Orion, Pegasus, Perseus, Piscis Austrinus, Sagittarius, Scorpius, Serpens, Taurus, Triangulum, Ursa Major, and Ursa Minor.


The Southern Hemisphere

Despite the necessity for up-to-date celestial charts to guide European explorers sailing across the globe from the late-fifteenth to the seventeenth centuries, maps of the southern skies remained largely blank until Uranometria’s release. It is likely that expansionist imperial powers deliberately withheld this navigational information to prevent rival empires from gaining an advantage at sea.

In this atlas, a 49th plate was included - this was one of the first European attempts at accurately depicting the stars of the southern hemisphere.

Black and white engraved chart of the southern hemisphere from Johann Bayer's 'Uranometria'. Radiating from the centre of the map and out to the left are a series of personified constellation with large and small stars surrounding them - the size relating to their brightness.

For the Southern Hemisphere, Bayer drew on Petrus Plancius’ for the positions of the stars in the southern skies and twelve new constellations first observed by Dutch navigators Pieter Keyser (1540–1596) and Friedrich de Houtman (1571–1627) during an exploratory voyage to the East Indies in 1595.

These new constellations were first depicted on a globe circa 1598 by Hondius. Here, you can see Bayer’s updated rendering of the southern night sky featuring the constellations: Chamaeleon, Phoenix, Triangulum australe (southern triangle), Apus (bird of paradise), Dorado (swordfish), Musca (fly), Tucana (toucan), Volans (flying fish), Grus (crane), Pavo (peacock), Hydrus (snake), and Indus (Indian).

A Lasting Impression

For this second printing of the work: the publisher - Johann Görlin - was committed to rectifying issues with the first edition. He removed the astronomical tables from the verso of the image plates. This not only maximised the final impression of each image plate, but made the publication more user-friendly. The tables were removed from all subsequent editions and printed as a separate star catalogue titled Explicatio characterum aeneis Uranometrias (1624).

Uranometria was revolutionary for its use of Bayer’s methodology of labelling (apparent) bright stars with Greek letters, each of which would define the ‘classes’ of magnitude, or brightness. This was also based upon the work of Danish astronomer Brahe.

The nomenclature system developed by Bayer - known as ‘Bayer letters’ - is still used by astronomers today. For example, the brightest star in the constellation Orion, Betelgeuse, is also known as Alpha (α) Orionis. According to the International Astronomical Union (IAU), this labelling has been extended to apply to about 1,300 stars. Despite issues with the accuracy in Bayer's new system, this would remain the standard until an updated nomenclature scheme by English astronomer John Flamsteed would become popular 200 years later in the first quarter of the eighteenth century.

It is argued by scholars whether this is indeed the ‘first complete star atlas’. Fifteen years prior to Uranometria, Giovanni Paulo Gallucci published Theatrum Mundi (1588), which presents fairly accurate star charts on a trapezoidal projection and using Copernicus’ De Revolutionibus (1543) as a guide for positioning.

The popularity of Bayer’s remarkable atlas meant that it would run into almost a dozen editions between 1603 and 1689, and would serve as a standard reference for astronomers for two centuries.

Explore The Sunderland Collection's copy of Uranometria in brilliant detail here on Oculi Mundi.

References