Light is sweet! and it is pleasant for the eyes to see the sun.
—Ecclesiastes 11:7
The Sun has been an object of admiration since the dawn of man. Ancient civilizations, including the Ancient Egyptians, Aztecs, and Incas, revered solar deities. The Greek scientists Anaxagoras, Aristarchus, and Ptolemy made important early solar observations. Intensive scientific research on the Sun reached its modern form with the advent of telescopes during the Scientific Revolution in Western Europe.
Catholic astronomers, including numerous Jesuits, have a storied history of solar research. This article will highlight, in rough chronological order, four Jesuit priests who have made foundational contributions to our understanding of the Sun:
- Christoph Scheiner (1573/75–1650)
- Angelo Secchi (1818–1878)
- Stephen Joseph Perry (1833–1889)
- Gyula Fényi (1845–1927)
1. Christoph Scheiner: The Jesuit Astronomer Who Unlocked the Sun’s Rotation
The German Jesuit Christoph Scheiner (1573/75–1650) conducted pioneering observations of sunspots. Sunspots, now known to be dark spots on the surface of the Sun from concentrations of magnetic flux, were known to ancient and medieval astronomers but were not studied with telescopes until the seventeenth century. Because it is extremely dangerous to observe the Sun directly through a telescope, Scheiner developed a helioscope to project the Sun’s image onto a surface.
Portrait of Christoph Thomas Scheffler / Public domain via Wikimedia Commons
Through his systematic sunspot observations, Scheiner made two important discoveries in solar physics. First, by tracking sunspot paths across the solar disk, he showed that the Sun’s rotational axis is inclined with respect to the Earth’s orbital plane. Second, he discovered that the rotation of the Sun at its equator is more rapid than at higher latitudes (solar differential rotation).
He also observed atmospheric effects on the Sun, including the apparent elliptical form of the Sun near the horizon and parhelia (bright spots on the sides of the Sun).
Scheiner published his research in several works, including the influential Rosa Ursina Sive Sol. A lunar crater is named in his honor.
2. Angelo Secchi: The Jesuit Astronomer Who Pioneered Stellar Classification
The Italian Jesuit Angelo Secchi (1818–1878) is considered one of the fathers of astrophysics. By observing and analyzing over 4,000 stars, Secchi developed the first system of stellar classification (the five Secchi classes). Secchi is considered the discoverer of carbon stars, which comprise a distinct Secchi class.
Angelo Secchi in Popular Science Monthly Volume 12 / Public domain via Wikimedia Commons
Secchi also compiled data on over 10,000 binary stars, discovered three comets, studied the rings of Saturn, made early observations of the spectra of Uranus and Neptune, and invented scientific instruments.
Secchi’s contributions to solar research are monumental. In his observations of the 1851 eclipse, he was one of the first to apply photography to the study of celestial bodies. He measured and compared the temperature of the solar disk at its center and at its edges, demonstrating that the center emits almost twice as much radiation. He organized expeditions in 1860 (Alicante, Spain) and 1870 (Augusta, Sicily) to observe solar eclipses. In 1877, he discovered solar spicules, jets of plasma in the Sun’s chromosphere. He made a long series of observations of sunspots, studying their forms, types, movements, positions, and sizes. His book, Le Soliel, became a standard work on the Sun.
A lunar crater, a Martian crater, and an asteroid are named in his honor.
3. Stephen Joseph Perry: The Jesuit Astronomer Who Travelled the World to Study the Sun
The English Jesuit Stephen Joseph Perry (1833–1889) served as director of Stonyhurst Observatory in Lancashire, England. Perry studied the spectra of sunspots and confirmed the 11-year solar cycle discovered by Samuel Heinrich Schwabe. He also studied faculae (bright spots in the photosphere), solar protuberances, the chromosphere, and the relationship between solar activity and magnetic storms. To aid his research, he prepared 3,800 drawings of the Sun’s surface.
Stephen Joseph Perry in Popular Science Monthly Volume 50 / Public domain via Wikimedia Commons
Perry participated in several expeditions related to the Sun. In 1874, he travelled to the Kerguelen Islands in the South Indian Ocean to observe the 1874 transit of Venus across the Sun. In 1882, he headed a similar expedition to Madagascar. Perry’s observations (and those of other astronomers) were used to make a more accurate measurement of the distance from the Earth to the Sun. Perry also participated in four expeditions to observe solar eclipses: Cadiz, Spain (1870), Pogost, Russia (1887), Carriacou, Caribbean (1887), and the Salut Isles, French Guyana (1889).
Perry was a Fellow of both the Royal Society and the Royal Astronomical Society.
4. Gyula Fényi: The Jesuit Astronomer Who Tracked Solar Prominences
The Hungarian Jesuit Gyula Fényi (1845–1927) was another prolific observer of the Sun. In 1885, he became director of the Haynald Observatory in Kalocsa, Hungary. Over a period of several decades, he made over 40,000 observations of sunspots, solar prominences, and faculae.
Commemorative plaque on the birthplace of Gyula Fényi (1845–1927), Zátonyi Sándor (ifj.), Fizped / CC BY-SA 3.0 via Wikimedia Commons
Fényi showed a correlation between the number of solar prominences and the number of sunspots, theorizing that they have the same origin. He observed that the chromosphere is depressed over sunspots. He also studied the relationship between large prominences and magnetic storms.
A lunar crater and an asteroid are named in his honor.
The Lasting Legacy of Jesuit Astronomers and the Sun
These eminent scientists and men of the Church help us appreciate the words of Psalm 113:3:
“From the rising of the sun to its setting, let the name of the Lord be praised.”
*Cover image: Cropped version of NASA Goddard Space Flight Center / CC BY 2.0 via Wikimedia Commons
