Johannes and Elisabetha Hevelius

German-Polish astronomers

• Elisabetha Hevelius
• Born: c. 1647
• Birthplace: Gdańsk?, Poland
• Died: 1693
• Place of death: Gdańsk?, Poland

• Johannes Hevelius
• Born: January 28, 1611
• Birthplace: Gdańsk, Poland
• Died: January 28, 1687
• Place of death: Gdańsk, Poland

Johannes and Elisabetha Hevelius compiled the most accurate nontelescopic catalog of the stars. Johannes established an observatory in Gdansk, compiled detailed maps of the Moon, and published a book describing many comets, including four that he discovered. Elisabetha published a collection of engravings of constellations, including eleven new constellation groupings, seven of which are still in use.

Early Lives

Johannes Hevelius (hay-VAY-lee-uhs) was born to a noble family of at least ten children. His father was a prosperous property owner who operated a brewery. His early education was at a gymnasium in Gdansk from 1618 to 1624. He then spent three years at a school near Bromberg, Poland, before returning to the Danzig gymnasium for three more years. There he studied under a tutor who gave him private lessons in astronomy and instrument-making, in addition to the regular curriculum.

Johannes traveled to the University of Leiden in the Netherlands in 1630, where he studied law for one year, plus some mathematics and optics. During the next two years, he visited several scientists in Paris. He then returned to Gdansk to work in his father’s brewery and to study the constitution of Gdansk. In 1635, he married Katharina Rebeschke, the daughter of a wealthy Gdansk landowner. After observing the solar eclipse of June 1, 1639, Johannes began a lifetime of astronomical work and a long career of civic responsibilities.

In the year following his first wife’s death in 1662, Johannes married Catherina Elisabetha Koopman, the well-educated sixteen-year-old daughter of a wealthy merchant. Although she was thirty-six years younger than her husband, she became his chief assistant in his astronomical work while hosting many visiting astronomers and raising three daughters.

Lives’ Work

Johannes devoted his life to civic duties, corresponded with foreign astronomers, and worked on astronomy. His first civic office in Gdansk, begun in 1641, was honorary magistrate; in 1651, he became a city councillor. The astronomers he communicated with included the Dutchman Christiaan Huygens , who discovered the rings of Saturn in 1656; John Flamsteed, who was the first royal astronomer in England; and Edmond Halley , who first demonstrated the elliptical orbits of comets and became the second royal astronomer in England. His major occupation, however, was astronomy.

Starting with a small upper room as an astronomical observatory, Johannes added a small roofed tower in 1644, and later built a platform on his house with both a stationary and a rotating observatory. In 1644, he was the first to observe the phases of Mercury, further confirming the heliocentric system. After his father died in 1649, he took over the brewery and used the extra funds for telescopes and other astronomical equipment, which made his observatory, called Sternenburg, one of the finest in the world. He also manufactured his own instruments in his own workshop and had a printing press for publishing his observations.

In 1647, Johannes published his first important work, an atlas of the Moon called Selenographia: Sive, lunae descriptio (reproduced map, with English translation, 1966). In the introduction to this book, he illustrates and describes his optical lathe for grinding telescope lenses. He also describes several telescopes, including the largest one, which was some 11 feet long and had about a 50-power magnification. He includes a drawing of Saturn with two semicircular handles, records of the movements of the moons of Jupiter, and observations of sunspots and eclipses. In the rest of the book, he describes lunar markings, the apparent lunar motions called librations, and drawings in his own hand of the Moon. His engravings of the lunar surface are among the best of the seventeenth century and introduce many of the names of lunar craters, mountains, and other features that are still used today.

Johannes’s second great work, Cometographia (study of comets), published in 1668, twenty-one years after his first book. Following some introductory engravings, including one of his house and observatories, he turns to discussion of the comet of 1652 and gives evidence contrary to Aristotle that it is located in space beyond the Moon. He also provides extensive information about comets of the two preceding centuries, including four that he discovered, and suggests that they move on parabolic paths around the Sun at the focus.

Johannes described his work in designing and making his astronomical instruments (celestial machines) in a two-volume work called Machina coelestis (1679), partially translated as The Illustrated Account Given by Hevelius in His “Machina celestis” of the Method of Mounting His Telescopes and Erecting an Observatory (1882). The two volumes describe more than a dozen large (up to 6 feet) quadrants and sextants made of copper and wood for measuring celestial positions, many of them based on designs of the Danish astronomer Tycho Brahe but with even greater accuracy than those of Brahe. He also described the design of several long telescopes with focal lengths ranging from about 25 to nearly 150 feet and lenses up to 8 inches in diameter, including the difficulties of mounting such large instruments. His longest telescopes turned out to be nearly useless, however.

After several assistants either died or were found to be unsatisfactory, Johannes opened his observatory to his second wife Elisabetha, who became his most accurate and diligent observer. She is shown in two plates of Machina coelestis assisting in Johannes’s observatory. For about ten years, she helped to run the observatory; in 1679, Johannes’s house, observatories, instruments, workshop and most of his papers were destroyed by a fire. By the end of 1681, the observatory was rebuilt, but with fewer and inferior instruments. He labored for five more years in declining health before dying on his seventy-sixth birthday.

Elisabetha Hevelius carried on with the work after Johannes died and completed his most important collection of observations. Three years after his death, she published a catalog of the positions and magnitudes of 1,564 stars, a work called Prodromus astronomiae (1690; The Star Atlas , 1968), the largest star catalog to that date and the last one compiled without the aid of the telescope. It gave star positions to an accuracy of about one minute of arc, about twice as accurate as Brahe’s measurements. Also in 1690, Elisabetha published a volume of fifty-six engravings of constellations. Her Uranographia (study of the heavens) included eleven new constellation groupings with seven names that are still used.

Significance

Although Johannes Hevelius was one of the leading astronomers of the mid-seventeenth century and the most accurate of the declining breed of nontelescopic observers, he represents more of a transitional figure in the inevitable trend toward telescopic astronomy. He was challenged to use telescopic sights in place of plain sighting instruments by John Flamsteed and later by Robert Hooke . Hooke wrote a critical work on Hevelius’s Machina coelestis called Animadversions on the First Part of the Machina coelestis of the Honourable, Learned, and Deservedly Famous Astronomer Johannes Hevelius (1674). The resulting controversy led the Royal Society in England to sponsor a 1679 visit to Gdansk by Edmond Halley, who concluded that Johannes could determine stellar positions without a telescope as accurately as Halley could with one at that point in time. Seven years later, in private correspondence, Halley altered this conclusion in favor of telescopic sights.

In his lunar studies, Johannes produced the first true atlas of the lunar surface and the best descriptions of librational cycles up to his time, providing a sound basis for further work in this area. His comet studies were especially useful to Halley in determining the elliptical orbits of comets. His most valuable contribution was his catalog of stars, which was reprinted by Flamsteed in 1725 and used well into the eighteenth century. The completion of this catalog by Elisabetha Hevelius, along with fifteen years of work with her husband before he died, established her as one of the rare women who was in a position to make important contributions to science in the seventeenth century.

Bibliography

Bell, Louis. The Telescope. New York: McGraw-Hill, 1922. The first chapter of this book on “The Evolution of the Telescope” has several pages on the contributions of Johannes Hevelius to the early development of the telescope.

Field, J. V., and Frank A. J. L. James, eds. Renaissance and Revolution: Humanists, Scholars, Craftsmen, and Natural Philosophers in Early Modern Europe. New York: Cambridge University Press, 1993. This collection on issues in the scientific revolution includes an essay entitled “Johannes Hevelius and the Visual Language of Astronomy,” by Mary Winkler and Albert van Helden, with several copies of engravings from Johannes’s Selenographia.

Hevelius, Johannes. The Star Atlas. Introduced and edited by V. P. Sheglov. Tashkent, Uzbekistan: FAN Press, 1968. A reproduction of 56 plates of Johannes and Elisabetha’s star catalog, compiled in cooperation with the Institute of Astronomy at the Academy of Sciences of the Uzbek, formerly part of the Soviet Union. Includes bibliographic footnotes.

McPike, Eugene Fairfield. Hevelius, Flamsteed, and Halley: Three Contemporary Astronomers and Their Mutual Relations. London: Taylor & Francis, 1937. This book reviews the controversy over telescopic versus nontelescopic sighting instruments.

Montgomery, Scott L. The Moon and the Western Imagination. Tucson: University of Arizona Press, 1999. This book describes Johannes’s studies of the Moon in Chapter 11, “Johannes Hevelius: A Moon of Higher Origins,” including several copies of engravings from the Selenographia.