Johannes Hevelius-like incident


My 67th birthday is approaching, and it makes me think, oddly, of my daughter, a martyred king, a little-known constellation, an even more obscure astronomer, and a tea tray.

Canes Venatici, the Hunting Dogs, may be an obscure constellation, but it produces in me (in a convoluted way, as you shall see) an intensely emotional frame of mind. Every time I look at it, I think of a time three decades ago, when my then 4-year-old daughter rescued me from a terrible fate.

She was at her daycare center helping to take care of the pet gerbils by replacing the newspaper that lined the bottom of their cages. She noticed — to her horror and her everlasting credit — that I was staring up, figuratively speaking, from the bottom of the cage. My daughter, bless her heart, rescued the astronomy column, and me, from gerbil ignominy.

The incident reminds me of Johannes Hevelius, one of the great astronomers of the 17th century. Today, he is remembered for naming a few obscure constellations in patches of sky with stars so faint that the ancients had not bothered to name them. These constellations include such unfamiliar titles as Vulpecula, the Little Fox, and Canes Venatici, the Hunting Dogs.

Canes is a particularly interesting example. Hevelius split it off from a larger constellation, the more familiar Bootes, the Herdsman. Hevelius depicts Canes Venatici as two hunting dogs held on a leash by Bootes, the Herdsman. The dogs are chasing the Great Bear, nipping at its tail.

I used to think it odd that Bootes was using dogs to drive the bears. Enlightenment came as I was hiking through a National Forest in West Virginia. All of a sudden, the peaceful silence was pierced by the raucous noise of dogs baying and yelping in the distance.

Soon, we encountered a pack of four dogs barking wildly at a small black bear that had escaped their unwanted attention by climbing a tree. The dog’s owner stood to the side staring up at the now-defenseless bear.

My hiking companion, who was savvy to such matters, asked him what he used to “bring down” the bears. Without a word, he reached inside his hunting vest and pulled out a .44 Magnum revolver, the largest handgun I have ever seen, and held it up for us to admire.

My hunting companion commented that since it wasn’t bear-hunting season, then why was he treeing bears?

“Practice for the dogs,” the hunter replied with a wink.

Bootes’ bear-hunting companions would have been unfamiliar to the ancients who originally named the constellations. They saw the stars of Canes Venatici as Bootes’ upraised club. The Greek astronomer Ptolemy identified them as such in his seminal work the Almagest.

Much of our knowledge of Greek astronomy might have been completely lost without the effort of medieval Arab scholars, who translated important works like the Almagest into Arabic and thus preserved them. However, mistakes were inevitably made. In this case, the Greek word for “club” was translated into the Arabic word for a “spear with a hook.” When Ptolemy’s book was later translated into Latin, the “hook” part was again mistranslated, that time as “dogs.”

Canes Venatici certainly deserves the full-constellation status that Hevelius gave it. Its brightest star, Cor Caroli, the Heart of Charles, is among the most famous in astronomical and cultural history.

The star is about 120 light years distant (about 720 trillion miles), which puts it in our galactic neighborhood. The surprise comes when it is viewed in a small telescope. Cor Caroli is not one star, but two. Near the bright star you see is a much dimmer companion, making Cor Caroli a double, or binary star. The stars are separated from one another by about 60.5 billion miles, about 650 times the distance between the Earth and sun. Even at that distance, their gravitational attraction to each other causes them to be caught in a slow cosmic dance. They orbit one another every 8,000 years or so.

The main star shines 50 times more brightly than our sun and has about three times more stellar material. Even the dim companion has six times the brightness and nearly twice the mass of the sun.

The main star is a strange one, even by the broad standards of weirdness that must be applied to stars. All stars are composed of hydrogen and helium. However, Cor Caroli has an overabundance of heavier elements like mercury, silicon and europium.

Cor Caroli also has a much more powerful magnetic field than most stars. As a result, it generates enormous, dark starspots that cover a relatively large part of its surface. As the star rotates and different spots come into view, Cor Caroli varies significantly in its apparent brightness.

The Charles of the Heart of Charles is Charles I of England, one of that nation’s most vilified and praised monarchs. He was thrown from power in 1647 after a long civil war between the Royalists, who supported him, and the Parliamentarians, led by a staunchly fundamentalist religious sect called the Puritans.

The Parliamentarians declared a “republican” form of government deeply grounded in Puritan morality. On Jan. 30, 1649, having blamed the former king for all the death and destruction of the war, the Commonwealth lopped off the head of the unfortunate monarch.

The Commonwealth lasted only 11 years. Political instability, repressive religious intolerance, and strict, puritanical laws governing human behavior characterized its rule. In 1660, Charles II, son of the martyred king, returned from exile to England, and the monarchy was restored.

And so it was that on May 29 of that year, Charles II returned to London in triumph. That night, Sir Charles Scarborough, personal physician to Charles II, went outside to look up as the stars shone beautifully under a velvet-black sky.

It is difficult to say what drew Scarborough’s eye to a not particularly bright star in an obscure constellation named after hunting dogs. Perhaps it was his dead monarch’s love of the hunt, or perhaps he looked up randomly.

In any case, the brightest star in Canes Venatici seemed to shine more brilliantly than he had ever seen, as if it were the heart of the dead king swelling with pride at his son’s restoration to the throne.

The Scarborough part of the story is probably apocryphal. However, by 1673, the identification of the star with the king was so commonly accepted that English stellar cartographer Francis Lamb designated the star as Cor Caroli Regis Martyris, the Heart of Charles, the Martyred King.

Around the same time, Hevelius was creating his now-famous star maps. We are thus left with a stunningly weird image: the heart of a martyred king tossed casually in the midst of bear-hunting dogs.

Hevelius’s star maps are beautiful to behold because he was an artist as well as an astronomer. He illustrated them with fanciful figures depicting the mythological characters represented by the constellations. He lovingly engraved them on copper plates, which were used to print the maps in 1690, three years after his death.

Many of his other observations were done with telescopes of his own design. The telescopes of those days were made with lenses that split the light into separate colors and produced rainbow fringes that wiped out the fine detail. To reduce the problem,

Hevelius had to create telescopes scopes that were extremely long. One was 150 feet in length and was suspended from a 90-foot pole.

With that telescope and others like it, Hevelius arduously made the most detailed lunar observations of his time. Like his star maps, those his moon drawings were recorded on copper plates for later publication.

Only a few priceless copies of those moon and star maps remain. We would now consider the plates from which they were made important historical antiquities, but none of them survive.

After his death, his heirs made what money they could from the sale of his belongings. The lunar images were, after all, engraved on valuable copper. At least one of the precious plates was pounded into a tea tray.

We live in an age when the old is constantly pounded out to make the new. Beautiful old buildings fall to erect new ones. Beautiful old observatories face the wrath of mini-malls, Zmarts, and housing developments. Beautiful old ideas are replaced by trendy new ones that serve the ephemeral needs of the day. And profoundly significant humans like Hevelius are consigned to the bottom of history’s gerbil cage.

I am therefore saddened most of all at the thought of some unknown artisan pounding out the delicate contours of the lunar surface or intricate engravings of bears and hunting dogs so that beverages could be served.

Beware, dear readers, the physical and intellectual edifices you tear down. Soon enough, your time will come. And thus, for myself and for all of you, I pray this fervent prayer: May fate spare us from our own personal tea trays. Lord, lord, lord, protect us from the gerbil cage.

By Tom Burns


Tom Burns is the former director of the Perkins Observatory in Delaware.

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