David and Johannes Fabricius
David and Johannes Fabricius were influential figures in early modern astronomy, with significant contributions that helped shift scientific understanding of celestial phenomena. David Fabricius, a Lutheran pastor and cartographer, made a groundbreaking discovery of the first periodic variable star, originally named Omicron Ceti, later known as Mira, in 1596. He established an observatory in Osteel, where he made notable observations, including the supernova of 1604, and was recognized by contemporaries like Johannes Kepler as a leading astronomer. His son, Johannes Fabricius, studied medicine but developed a strong interest in astronomy, particularly during his time in Leyden. He became the first to make telescopic observations of sunspots in 1611, contributing to the understanding of solar phenomena. Their work collectively challenged the long-held Aristotelian view of a perfect and constant universe, marking a significant advancement in astronomical science. Tragically, both faced untimely deaths—Johannes at the young age of twenty-nine, and David later due to a violent altercation. In recognition of their contributions, a crater on the Moon is named "Fabricius," highlighting their lasting impact on the field of astronomy.
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Subject Terms
David and Johannes Fabricius
German astronomers
- David Fabricius
- Born: March 9, 1564
- Birthplace: Esens, East Frisia (now in Germany)
- Died: May 7, 1617
- Place of death: Osteel, East Frisia (now in Germany)
- Johannes Fabricius
- Born: January 8, 1587
- Birthplace: Resterhafe, East Frisia (now in Germany)
- Died: March 18, 1616
- Place of death: Osteel, East Frisia (now in Germany)
David Fabricius discovered the first periodic variable star, and his son, Johannes, was the first to make telescopic observations of sunspots, although some contend it was Galileo who did so before Johannes. Johannes was, however, the first to publish on the subject of sunspots. Also, David and Johannes determined that the Sun rotates on its axis.
Early Lives
Not much is known about the early lives of David and Johannes Fabricius (fah-BREET-see-uhs). “Fabricius” is a Latin form of the surname “Faber.” In the early 1580’s, David Fabricius studied in Resterhafe to become a Lutheran pastor. By 1585, he was serving as a pastor in the small town of Osteel. He was the father of seven children, four daughters and three sons.
In addition to being a respected clergyman, David was an adept cartographer and compiled the first map of East Frisia in 1589. He was very interested in science, particularly astronomy, and through correspondence and personal visits became good friends with astronomers Tycho Brahe and Johannes Kepler. He met with Brahe to discuss astronomy and astrology at Wandsburg Castle (in southwestern Germany) in 1598 and also in Prague in 1601.
Johannes Fabricius, David’s second child and first son, studied medicine between 1604 and 1610 in Helmstedt and Wittenberg, then in Leyden. While at Leyden, his interest in astronomy developed. He became very interested in using a telescope to make observations of stars and planets. In 1610, he returned to Osteel and began to practice as a physician, taking with him a telescope. He apparently continued some further medical studies at Wittenberg in 1611.
Lives’ Work
By the mid-1590’s, David Fabricius, by this time an accomplished pastor and mapmaker, also was an astute observational astronomer. On August 3, 1596, he discovered without a telescope a star originally named Omicron Ceti. The star was later renamed Mira, meaning “wonderful.” Because of the star’s brightness, David thought initially that Mira was a nova. With subsequent observations, he noticed that the star was sometimes bright enough to be easily seen with the naked eye, while at other times it faded out of sight. He had discovered the first periodic, pulsating variable star, a discovery that refuted Aristotle’s notion that the heavens were constant and perfect.
From an observatory that he established in Osteel, David observed the supernova of 1604 near the conjunction of Jupiter and Mars and reported his findings in both German and Latin publications. Kepler referred to David in some of his writings as the second best astronomer in Europe next to Tycho Brahe.
As a practicing physician in Osteel, Johannes Fabricius devoted much of his spare time to astronomical observations using the telescope that he had obtained in Leyden. On March 9, 1611, he made the first telescopic observations of sunspots. Apparently, his father, David, had observed sunspots many years earlier without a telescope, as had Korean and Chinese astronomers and early English astronomer John of Worcester. Shortly after his first observations of sunspots, Johannes made geometrical drawings of his findings and shared them with his father. Subsequently, they made numerous additional observations, typically just after sunrise and just before sunset. Finding moving blemishes on the Sun was another refutation of Aristotle’s premise that the heavens were perfect and constant.
Because of the eye inflammation and pain that came from viewing the Sun directly, David and Johannes soon adopted and perfected the camera obscura technique. With this method, an image of the Sun is projected onto a suitable surface in a darkened room by passing sunlight through a pinhole opening that is made in the covering of a window in the room. The camera obscura was a safe way to observe the sun, and, also, it gave a clearer view of the solar disk. Between March and June of 1611, David and Johannes recorded numerous observations of sunspots. They noted that spots appearing on the western edge of the Sun would reappear on the eastern side after approximately twelve days. They made the correct interpretation of sunspot movement by concluding that the Sun must rotate on its axis. The two differed in their opinion as to where the spots were located, however. Johannes believed the spots to be on the surface of the sun, whereas his father thought that they might be clouds or planetary objects passing by the Sun and not part of the Sun itself.
Johannes wrote De maculis in sole observatis (narration on spots observed on the sun) and published the booklet in 1611 using the name “Johann Goldsmid,” a version of his name evidently used while he was studying in Leyden. Unfortunately, observation times and dates, as well as sketches of the spots, were not included in the treatise. Although it was sold at a book fair in Frankfurt in the fall of 1611, it remained in obscurity until it was rediscovered and publicized in 1723. In the meantime, Galileo and Christoph Scheiner had each claimed credit for making the first telescopic observations of sunspots during the latter part of 1611 or early 1612. Due credit was not given to David and Johannes Fabricius until more than one hundred years after their important work.
Johannes died of unknown causes in 1616 at the very young age of twenty-nine. Almost one year later, David suffered a surprising death at the hands of an irate member of his Lutheran congregation. While presenting a sermon, the elder Fabricius had chastised farmer Frerik Hoyer for stealing a goose. Later, Hoyer confronted David in the church yard and struck him in the head with a shovel, killing the pastor. David was depicted in a novel by nineteenth century French writer Jules Verne. In Verne’s Autour de la lune (1870; From the Earth to the Moon… and a Trip Around It, 1873), David is portrayed as an astronomer who viewed inhabitants on the moon with his telescope.
In honor of the contributions of David and Johannes to astronomy, a large impact crater on the Moon was named “Fabricius.” The crater is located within the northeastern part of the Janssen walled plain in the southern hemisphere of the Moon and has a diameter of approximately 90 kilometers. It is not known, however, if the crater was named originally to honor both David and Johannes Fabricius, or to honor just one.
Significance
Astronomical observations made by David Fabricius initiated the study of periodic variable stars by other astronomers, leading to an explanation of pulsating star phenomena in terms of varying luminosity and surface temperature. Observations of sunspot phenomena made by Johannes and David Fabricius advanced the use of the camera obscura method for investigating the Sun and motivated other astronomers to study sunspots. Interpretation of the day-by-day movement of sunspots by David and Johannes Fabricius led them to conclude correctly that the Sun rotates on its axis. The younger Fabricius was the first astronomer to publish the results of such findings. Their discovery of pulsating variable stars and telescopic observations of sunspots led many astronomers to revise their own theories that the heavens were perfect and constant, as originally thought by Aristotle.
The work of David and Johannes Fabricius was noted by many contemporary astronomers, including Johannes Kepler, Michael Mästlin, and Simon Marius. David and Johannes Fabricius were instrumental in stimulating the curiosity of other astronomers to carefully study and correctly interpret observations of the stars.
Bibliography
Brody, Judit. The Enigma of Sunspots: A Story of Discovery and Scientific Revolution. Edinburgh: Floris Books, 2002. Brody relates the fascinating story of the discovery of sunspots by David and Johannes Fabricius and the efforts that have been made since their time to describe and understand sunspots. Includes bibliographical references and color illustrations.
Christianson, John Robert. On Tycho’s Island: Tycho Brahe, Science, and Culture in the Sixteenth Century. New York: Cambridge University Press, 2002. This work tracks the history of Tycho Brahe—philosopher, chemist, and astronomer—and discusses his interaction with David Fabricius. David corresponded and visited with Brahe and discussed some of his astronomical discoveries with him. Includes bibliographical references and index.
Drake, Stillman, Noel M. Swerdlow, and Trevor Harvey Levere. Essays on Galileo and the History and Philosophy of Science. Vol. 1. Toronto: University of Toronto Press, 1999. This volume includes a discussion on the controversy over who discovered sunspots—David and Johannes Fabricius, Galileo, Christoph Scheiner, or someone else. Includes bibliographical references and index.
Kepler, Johannes, and Edward Rosen. Kepler’s Somnium: The Dream: Or, Posthumous Work on Lunar Astronomy. New York: Dover Books, 2003. Recounts some of Kepler’s accomplishments and ideas, including his dream about a trip to the Moon, and tells of the friendship of David and Johannes Fabricius with Kepler.