The secret of Sextans

Of all the constellations in the April night sky, one of the dimmest and most ignored is Sextans the Sextant. Polish astronomer Johannes Hevelius created Sextans Uraniae (now just Sextans) in 1687 to commemorate the large sextant he and his wife, Elisabeth, used to measure star positions. A fire, he said, consumed the instrument in September 1679 when Vulcan (the Roman god of fire) overcame Urania (the muse of astronomy).
 
Although ambivalent toward astrology, Hevelius thought the new constellation’s celestial location seemed appropriate: It lies between Leo the Lion (a fire sign) and Hydra the Water Snake (also associated with fire). And it turns out a fire, at least of the creative kind, might have resulted in a famed historical mystery associated with the constellation Sextans’ stars.

A heated imagination?
In April 1643, European observer Antonius Maria Schyrleus de Rheita claimed to have seen among the stars of Leo (those which Hevelius later turned into Sextans) the holy Sudarium Veronicae — the handkerchief Saint Veronica used to wipe the face of Jesus on his way to Calvary. As depicted in the Sixth Station of the Cross, the cloth then took on the impression of Christ’s face. Interestingly, and perhaps tellingly, the Catholic Church’s Capuchin Order, of which de Rheita was a friar, has claimed possession of this cloth since the 16th century.

Is it surprising, then, that de Rheita envisioned the cloth among the stars of Leo, the “King” of the zodiac, near the point where the ecliptic intersects the celestial equator? This is the point of the autumnal equinox, when, spiritually, the Sun begins a descent toward its own Calvary.

Certainly, we should not fault de Rheita for applying his inspiration to the stars, no more than we would Hevelius for picturing something of his personal interest in the region. But de Rheita appears to have had a colorful imagination. In 1642, for instance, he claimed that a parade of shooting stars passed in front of the Sun for two weeks, resulting in a dimming of our star’s light.

De Rheita avidly pursued astronomy and optics throughout the 1640s. In 1645, he published his most famous work, Oculus Enoch et Eliae, in which he introduced new telescope and eyepiece designs. The work not only gave us the words ocular and objective but also the first drawing of the Moon as seen through a telescope that inverts the image. A lunar crater (Rheita) and valley (Vallis Rheita) are named in his honor.

His Oculus also included mention of his 1643 sighting of the Sudarium Veronicae, which he made through a binocular telescope of his own design — the first ancestor of today’s binoculars. In the 19th century, however, English astronomer John Herschel downplayed de Rheita’s sighting, saying, “Many strange things were seen among the stars before the use of powerful telescopes became common.”

Got the time?
If you’d like to search for this lost and forgotten asterism, Admiral William Henry Smyth said, in his 1844 work, A Cycle of Celestial Objects, that it lies about 9° southeast of Regulus (Alpha [α] Leonis). Later editions also included a representation of the figure, but gave no apparent size or orientation. Clearly, seeing the pattern (if it exists) won’t require a “powerful telescope,” but perhaps only binoculars … and your imagination.
 
As always, let me know what you do or don’t see at someara@interpac.net.