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Mapping the Solar System
By Nick Kanas, M.D.

Systema Solare et Planetarium ex Hypothesi Copernicana…, by Johann Doppelmayr and Johann Homann gives special prominence to the heliocentric solar system as developed by Copernicus.

From 1500 to 1800 the beauty and the quality of European celestial atlases were unmatched. Ancient Greek heroes and heroines roamed the night sky. Sea monsters bared their teeth, serpents slithered, and winged horses paused in flight. But the familiar constellations were gradually joined by new illustrations of the heavens, fueled by changing ideas that science and observation brought to the perceptions of Earth, the Sun, and their relationship to each other and the universe.

Celestial and even geographical atlases often contained plates depicting more than just constellations. They also included diagrams of the solar system and illustrations of the planets that reflected the evolution from ancient to contemporary concepts — and in some cases the competition between old and new ideas. These maps of the heavens served an important function in cartography. As the distinguished geographer and cartographic historian Norman Thrower has observed, “Viewed in its development through time, the map details the changing thought of the human race, and few works seem to be such an excellent indicator of culture and civilization.” Maps of the solar system not only illustrated the physical realm in space, but also placed the evolution of the assumptions and ideas represented on the maps in historical context.

A striking example is Andreas Cellarius’s Atlas Coelestis seu Harmonia Macrocosmica, published in 1660. Cellarius was the rector of the Latin school at Hoorn in northern Holland. His atlas contained a description of ancient and contemporary astronomical ideas, specific theories of such luminaries as Ptolemy, Copernicus, and Tycho Brahe, and more general issues related to constellations, planets, and the zodiac. The atlas was illustrated with twenty-nine ornamental engraved plates, among the most beautiful ever made. Elaborate cartouches typically framed the Latin titles of the plates, and around the main illustration were such baroque elements as putti in clouds, shells, and vines, as well as portraits of famous astronomers and astronomical instruments.

However, the main themes of the plates were serious business. Plate 16, for example, titled Theoria Solis Per Eccentricum Sine Epicyclo, depicts the eccentric orbit of the Sun around Earth as developed by the Greek astronomer Hipparchus (circa 161–126 b.c.) and refined by Claudius Ptolemy (circa a.d. 100–178), an astronomer working in Alexandria. The Greeks excelled in spherical geometry and tried to understand the structure of the cosmos and the motions of heavenly bodies. Philosophical considerations of mankind’s role in the universe and the perfection of the circular shape, however, led to a belief in an Earth-centered universe, with stars and planets orbiting in perfect circles at constant velocities.

The Greeks knew that the interval from the autumnal equinox to the vernal equinox (187 days) was longer than the interval from the vernal equinox to the autumnal equinox (178 days). How could one account for this discrepancy while still maintaining a theory that depended on a perfectly circular orbit? Plate 16 illustrates a simple solution: theorize that the Sun goes around Earth in an off-center eccentric orbit. Accordingly, the line labeled Aequinoctialis seu Colurus Aequinoctiorium runs left to right through the center of Earth, with less of the Sun’s orbit below than above this line, accounting for a shorter inter-equinox transit.

Plate 16 also shows other ideas about the arrangement of heavenly bodies. At the bottom right is a schematic diagram of the Sun revolving in a small orbital circle, called an epicycle, as it moves around its Earth-centered orbit, called a deferent. Depending on how fast the Sun revolves in its epicycle, and whether it moves clockwise or counterclockwise, it can occupy a number of positions with reference to Earth as it moves along the deferent orbit. In the schematic, where the combination of movements results in the placement of the small Sun figures shown, a line connecting them would approximate an eccentric orbit, demonstrating that an epicycle/deferent model may be made to be equivalent to an eccentric model. But which model is correct, the eccentric or the epicycle/deferent? To us, neither, because we know that Johannes Kepler (1571–1630) demonstrated that the planets revolve around the Sun in elliptical orbits with speeds that vary inversely with the distance of the planet from the Sun. To the Greeks, however, both models were correct, because they both accounted for observations of the heavens and allowed mathematical predictions to be made — in this case, where the Sun could be located in the sky.

Another celestial topic depicted in star atlases involved the competition between geocentric and heliocentric models of the universe. Although Aristarchus and other Greek writers suggested that Earth and other planets revolved around the Sun, the predominant view put Earth at the center of the universe. Ptolemy embraced this model around a.d. 150 in his summary of Greek astronomical knowledge, Almagest. His views held sway until 1543, when the Polish astronomer Nicholas Copernicus (1473–1543) published his On the Revolutions of Heavenly Spheres, which endorsed a heliocentric system (but also continued the practice of viewing the planets as moving around the Sun in circular orbits and utilized eccentrics, deferents, and epicycles). However, resistance from the church as well as conservative universities and astronomers delayed widespread acceptance of his views for more than a century, and for decades celestial and geographical atlases depicted competing models of the universe.

A beautiful example of this duality is displayed on a plate by Johann Doppelmayr (1671–1750), a German astronomer and professor of mathematics in Nuremberg who for more than twenty years collaborated with Johann Homann (1664–1724), geographer to the kaiser of the Holy Roman Empire and founder of a cartographic publishing house in Nuremberg. Together Doppelmayr and Homann produced a series of charts and a celestial atlas containing a wealth of astronomical information. One plate, Systema Solare et Planetarium ex Hypothesi Copernicana…, illustrates the state of astronomical knowledge in the early 1700s. In the upper left corner are representations of the then-known planets along with the Sun. In the upper right corner are baroque embellishments, with heavenly clouds and other star systems. In the lower left corner is a depiction of the solar eclipse of 12 May 1706 (with California represented as an island). And in the center is a spectacular representation of the Copernican world view as described by the Dutch astronomer Christiaan Huygens (1629–95), complete with sunburst, orbits of the planets and their moons revolving concentrically around the Sun, textual and numerical information on the proportionate diameters of the planets, and the rest of the surrounding universe in the form of the twelve constellations of the zodiac.

Copernicus’s ordering of the planets known at the time — Mercury, Venus, Earth, Mars, Jupiter, and Saturn — remains the same today, although the moons depicted for Jupiter and Saturn were not discovered until well after the great Polish astronomer died. In the lower right corner below the illustration of a lunar eclipse are representations of three cosmological systems as introduced by Urania, the goddess of astronomy. The first, on the left, is Ptolemy’s system, which is partially obscured by contemporary astronomical instruments (perhaps implying that modern science has dispatched this view). Earth is in the center, around which orbit its moon, Mercury, Venus, the Sun, Mars, Jupiter, Saturn, and the fixed stars. The middle illustration shows a hybrid system developed by the Danish astronomer Tycho Brahe (1546–1601). In Tycho Brahe’s model, the Moon and the Sun orbit Earth — but Mercury, Venus, Mars, Jupiter, and Saturn orbit the Sun, giving it some semblance of grandeur. The fixed stars, however, continue to surround Earth, bestowing on it the heavenly prominence Tycho Brahe felt it deserved. Note that this arrangement created the awkward situation where Mars could come between Earth and the Sun as it moved along its orbit. The final model, the Copernican system, is labeled sic ratione (i.e., according to reason). This labeling and the dominance of Copernicus’s ideas on this plate clearly indicate the opinions of Doppelmayr and Homann, even though alternative models are included for historical purposes.

Comparing celestial views was not solely a European pastime. The Cihannuma of 1732, the first printed Turkish atlas, was developed by Katip Celebi (1609–57) and reflected the state of Ottoman celestial knowledge in the mid-1600s. One of its charts compares the solar systems of Copernicus and Tycho Brahe, with no attempt to give either idea dominance. At the bottom left, two diagrams illustrate the mechanism for the apparent retrograde motion of both a superior and an inferior planet. At the bottom right, the first diagram depicts a superior planet’s orbit (complete with retrograde loops) through the course of a year as seen from Earth, and the second diagram shows how Earth’s axis points in the same direction, a phenomenon known as the third motion of Earth, as it proceeds along its orbit.

In On the Revolutions of Heavenly Spheres, Copernicus described three motions of Earth that account for important visible movements in the sky. The first is Earth’s rotation on its axis from west to east, which accounts for the movement of the Sun and stars from east to west. The second motion is Earth’s revolution around the Sun from west to east (counterclockwise), which accounts for the eastward drift of the Sun throughout the year. The third motion is a compensatory east-to-west (clockwise) motion in declination that allows Earth’s axis to point in the same general direction as it revolves around the Sun.

Earth’s second and third motions are beautifully illustrated on a print from an atlas by Vincenzo Coronelli (1650–1718), Corso Geografico Universale, published in 1692. Coronelli, a Franciscan priest and geographer royale to Louis XIV of France, produced more than four hundred maps and numerous globes, all from his Franciscan monastery outside of Venice. His prints are richly illustrated and handsomely embellished with baroque elements, including seashells, floral motifs, ribbons, curtains, and bold human figures. Their content is also accurate. His illustration of Earth’s third movement, for example, demonstrates how Earth’s axis points in the same direction during its yearly revolution and how the Sun appears low during winter in the Northern Hemisphere and high during summer.

Contemporary views of the planets and Earth’s moon were also depicted in early atlases, of which the Doppelmayr plate is but one example. Another is from Atlas Nouveau Portatif a’ l’Usage des Militaires, by the Parisian geographer and publisher Jean Crepy (circa 1730–70), published in 1767. Titled Le Globe Celeste, the copper engraving illustrates several components of the solar system as described by prominent celestial observers of the era. At the top center is an Earth-like depiction of the Sun promoted by the Jesuit priest Athanasius Kircher (1602–80), complete with mountains, volcanoes, and clouds. Also shown are features supposedly seen on several planets by Giovanni Cassini (1625–1712), the first director of the Paris Observatory. Additional diagrams depict Sun-Earth relationships, two planispheres of the constellations, and, at the bottom, maps of the Southern and Northern Hemispheres (without the Pacific Northwest in the latter, but showing California as a peninsula, probably after Delisle’s famous Hemisphere Septentrional of 1714).

One of the most famous depictions of Earth’s moon, Tabula Selenographica, a Doppelmayr/Homann print published around 1730, shows two systems of lunar cartography side by side. On the left is the system developed by the Polish astronomer Johannes Hevelius (1611–87), who published the first lunar atlas in 1647. Hevelius conceived of a correspondence between the geographies of Earth and its moon, and he named many lunar features after similar ones found on Earth. This correspondence can easily be seen by rotating the plate 90 degrees counterclockwise. Seen from this angle, Mare Mediterraneum looks similar to the Mediterranean Sea, accompanied by the landform Sicilia and its famous peak Mt. Aetna in the middle.

The other lunar picture illustrates the system developed by Giovanni Riccioli (1598–1671), an Italian Jesuit scholar who in 1651 published his lunar map with features named after famous people and scientists. Aetna becomes the crater Copernicus, and the crater at the center of the prominent ray system in the lunar south becomes Tycho rather than Mt. Sinai, as envisioned by Hevelius. For more than 140 years, these two cartographic systems competed with each other, and atlases often included both models when describing the Moon, although perhaps not as dramatically as depicted in the print by Doppelmayr and Homann. Although Hevelius enjoyed great prestige and prominence, Riccioli’s simpler nomenclature eventually gained widespread acceptance and with few exceptions is still in use today.

Features of the solar system ranging from concentric to eccentric orbits of the planets, from geocentric to heliocentric arrangements of the heavenly bodies, from diagrams of retrograde planetary movements to Earth’s motions, and from depictions of planetary features to competing views of lunar landforms have been charted through time on maps of the heavens. Beautifully composed prints combined the prevailing notions with colorful figures that reflected both the intellectual and the artistic characteristics of the time in which they were made. In the true spirit of cartography, these maps of the solar system have served to help us find our way out of the terrain of ignorance and onto the road to understanding.

Dr. Nick Kanas is Professor of Psychiatry at the University of California and the Veterans Administration Hospital in San Francisco, where he does research on psychosocial issues affecting astronauts and cosmonauts. An amateur astronomer since childhood, he has been collecting antiquarian celestial books, atlases, and prints for more than twenty years. Dr. Kanas is a member of the California Map Society. He would like to thank Bill Warren for his helpful comments on a draft of this article.

All illustrations courtesy of Dr. Kanas from his private collection

Further Reading
Copernicus, Nicholas. On the Revolutions of Heavenly Spheres. Charles Glenn Wallis, trans. Amherst, N.Y.: Prometheus Books, 1995.
Crowe, Michael J. Theories of the World from Antiquity to the Copernican Revolution. Mineola, N.Y.: Dover Publications, 1990.
Heckrotte, Warren, and Sweetkind, Julie, ed. California 49. San Francisco: California Map Society, 1999.
Hoskin, Michael, ed. The Cambridge Illustrated History of Astronomy. Cambridge: Cambridge University Press, 1997.
Norton, John. The Norton History of Astronomy and Cosmology. New York: W.W. Norton & Company, 1995.
Snyder, George S. Maps of the Heavens. New York: Abbeville Press, 1984.
Stott, Carole. Celestial Charts: Antique Maps of the Heavens. London: Studio Editions Limited, 1995.
Thrower, Norman J.W. Maps & Civilization: Cartography in Culture and Society. 2nd edition. Chicago: University of Chicago Press, 1999.
Warner, Deborah J. The Sky Explored: Celestial Cartography 1500–1800. New York: Alan R. Liss, Inc., 1979.
Whitaker, Ewen A. Mapping and Naming the Moon: A History of Lunar Cartography and Nomenclature. Cambridge: Cambridge University Press, 1999.
Whitfield, Peter. The Mapping of the Heavens. London: The British Library, 1995.


Theoria Solis Per Eccentricum Sine Epicyclo, Plate 16 from Andreas Cellarius’s famous celestial atlas of 1660.


An Ottoman print from the Cihannuma suggests that Western concepts of the solar system had reached Turkey by the 1600s and that the level of astronomical knowledge was quite high


For nearly a century and a half, lunar cartographic systems developed by Hevelius and Riccioli competed with each other, as shown on Tabula Selenographica, a print by Doppelmayr and Homann published a


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