Uranometria

Uranometria

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Uranometria is the short title of a star atlas produced by Johann Bayer
Johann Bayer
Johann Bayer was a German lawyer and uranographer . He was born in Rain, Bavaria, in 1572. He began his study of philosophy in Ingolstadt in 1592, and moved later to Augsburg to begin work as a lawyer. He grew interested in astronomy during his time in Augsburg...

.
It was published in Augsburg
Augsburg
Augsburg is a city in the south-west of Bavaria, Germany. It is a university town and home of the Regierungsbezirk Schwaben and the Bezirk Schwaben. Augsburg is an urban district and home to the institutions of the Landkreis Augsburg. It is, as of 2008, the third-largest city in Bavaria with a...

, Germany
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...

, in 1603 by Christophorus Mangus under the full title Uranometria : omnium asterismorum continens schemata, nova methodo delineata, aereis laminis expressa. This translates to "Uranometria, containing charts of all the constellations, drawn by a new method and engraved on copper plates". The word "Uranometria" derives from Urania
Urania
Urania was, in Greek mythology, the muse of astronomy. Some accounts list her as the mother of the musician Linus. She is usually depicted with a globe in her left hand. She is able to foretell the future by the arrangement of the stars...

, Muse of the heavens and "uranos" (oυρανός) the Greek word for sky
Sky
The sky is the part of the atmosphere or outer space visible from the surface of any astronomical object. It is difficult to define precisely for several reasons. During daylight, the sky of Earth has the appearance of a pale blue surface because the air scatters the sunlight. The sky is sometimes...

 / heavens
Heavens
Heavens was an independent rock band featuring Matt Skiba of Alkaline Trio and Josiah Steinbrick. The duo signed to Epitaph Records and released their debut album, Patent Pending, on September 12, 2006....

. A literal translation of "Uranometria" is "Measuring the Sky" (to be compared with "Geometry"-"Geometria" in Greek, literally translated to "Measuring the Earth").

It was the first atlas to cover the entire celestial sphere
Celestial sphere
In astronomy and navigation, the celestial sphere is an imaginary sphere of arbitrarily large radius, concentric with the Earth and rotating upon the same axis. All objects in the sky can be thought of as projected upon the celestial sphere. Projected upward from Earth's equator and poles are the...

.

The pages of Uranometria were originally engraved on copper plates by Alexander Mair (ca 1562-1617). It contained 51 star charts. The first 48 pages represent the 48 Ptolemaic
Ptolemy
Claudius Ptolemy , was a Roman citizen of Egypt who wrote in Greek. He was a mathematician, astronomer, geographer, astrologer, and poet of a single epigram in the Greek Anthology. He lived in Egypt under Roman rule, and is believed to have been born in the town of Ptolemais Hermiou in the...

 constellation
Constellation
In modern astronomy, a constellation is an internationally defined area of the celestial sphere. These areas are grouped around asterisms, patterns formed by prominent stars within apparent proximity to one another on Earth's night sky....

s. The 49th page introduces 12 new constellations in the deep southern sky which were unknown to Ptolemy. The final two charts are planisphere
Planisphere
A planisphere is a star chart analog computing instrument in the form of two adjustable disks that rotate on a common pivot. It can be adjusted to display the visible stars for any time and date. It is an instrument to assist in learning how to recognize stars and constellations...

s labeled "Synopsis coeli superioris borea" and "Synopsis coeli inferioris austrina," or (roughly), "Overview of the northern hemisphere" and "Overview of the southern hemisphere."

Each plate includes a grid for accurately determining the position of each star to fractions of a degree
Degree (angle)
A degree , usually denoted by ° , is a measurement of plane angle, representing 1⁄360 of a full rotation; one degree is equivalent to π/180 radians...

. The positions used by Bayer to create the Uranometria were taken from the expanded 1,005 star catalog of Tycho Brahe
Tycho Brahe
Tycho Brahe , born Tyge Ottesen Brahe, was a Danish nobleman known for his accurate and comprehensive astronomical and planetary observations...

. Brahe's expanded list had circulated in manuscript since 1598 and was available in graphic form on the celestial globes of Petrus Plancius
Petrus Plancius
Petrus Plancius was a Dutch astronomer, cartographer and clergyman. He was born as Pieter Platevoet in Dranouter, now in Heuvelland, West Flanders. He studied theology in Germany and England...

, Hondius
Hondius
Hondius can refer to two possibly unrelated families of engravers and cartographers, who both moved from Flanders to the Dutch Republic in the 1590s:* Amsterdam family originating from Ghent:** Jodocus Hondius ** Jodocus Hondius II Hondius can refer to two possibly unrelated families of engravers...

, and Willem Blaeu
Willem Blaeu
Willem Janszoon Blaeu , also abbreviated to Willem Jansz. Blaeu, was a Dutch cartographer, atlas maker and publisher....

. It was first published in tabular form in Johannes Kepler
Johannes Kepler
Johannes Kepler was a German mathematician, astronomer and astrologer. A key figure in the 17th century scientific revolution, he is best known for his eponymous laws of planetary motion, codified by later astronomers, based on his works Astronomia nova, Harmonices Mundi, and Epitome of Copernican...

's Tabulae Rudolphinae of 1627.

The use of Brahe's catalog allowed for considerably better accuracy than Ptolemy's somewhat limited star listing. The stars listed in Uranometria total over 1,200, indicating that Brahe's catalog was not the only source of information used. Bayer took the southern star positions and constellation names for the 49th plate from the catalog of Dutch navigator Pieter Dirkszoon Keyser
Pieter Dirkszoon Keyser
Pieter Dirkszoon Keyser , a.k.a. Petrus Theodori, was a Dutch navigator who mapped the southern sky....

, who corrected the older observations of Amerigo Vespucci
Amerigo Vespucci
Amerigo Vespucci was an Italian explorer, financier, navigator and cartographer. The Americas are generally believed to have derived their name from the feminized Latin version of his first name.-Expeditions:...

 and Andrea Corsali
Andrea Corsali
Andrea Corsali was an Italian explorer who worked in the service of Giuliano di Lorenzo de' Medici of Florence and Lorenzo II de' Medici, duke of Urbino. Corsali traveled to Asia and the south seas aboard a Portuguese merchant vessel, writing home with accounts of the lands and peoples he...

, as well as the report of Pedro de Medina. Uranometria contains many more stars than did any previous star atlas, though the exact number is disputed as not all stars on the charts are labeled.

Each of the constellations' stars are overlayed on an engraved image of the subject of the constellation. For reasons unknown, many of the human constellations are engraved as figures seen from behind whereas they had traditionally been rendered as facing the Earth
Earth
Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...

. This oddity led to some confusion in the literal meanings of certain star names (e.g. the origins of several named stars refer specifically to "right shoulder" and the like, which would be incorrect given Uranometria's illustrations).

Uranometria introduced the Bayer star designations
Bayer designation
A Bayer designation is a stellar designation in which a specific star is identified by a Greek letter, followed by the genitive form of its parent constellation's Latin name...

, which are still used today. It also introduced several of the modern constellations.

Title page engraving


The engraved title page of Uranometria features an architectural motif with the full title in the center. On pedestals to either side stand figures of Atlas
Atlas
An atlas is a collection of maps; it is typically a map of Earth or a region of Earth, but there are atlases of the other planets in the Solar System. Atlases have traditionally been bound into book form, but today many atlases are in multimedia formats...

 and Hercules
Hercules
Hercules is the Roman name for Greek demigod Heracles, son of Zeus , and the mortal Alcmene...

. Inscriptions in the pedestals read, "Atlanti uetustiss astronom magistro" ("Atlas the earliest teacher of astronomy") and "Herculi uetustiss astronom discipulo" ("Hercules the earliest student of astronomy"). Across the top of the title page are engraved several additional figures. In the upper left is Apollo
Apollo
Apollo is one of the most important and complex of the Olympian deities in Greek and Roman mythology...

, personifying the sun. Top center is the Earth goddess Cybele
Cybele
Cybele , was a Phrygian form of the Earth Mother or Great Mother. As with Greek Gaia , her Minoan equivalent Rhea and some aspects of Demeter, Cybele embodies the fertile Earth...

 with a crown of stars and two lions on leashes. Upper right is Diana, personifying the moon, with a cape of stars. Beneath the title banner is a figure of Capricorn
Capricorn
Capricorn may refer to:* Capricornus, one of the constellations of the zodiac** Capricorn * Capricorn , a manga series created by Johji Manabe* Capricorn , Jay Chou's 9th studio album...

and beneath that a view of Augsburg.

External links