Johannes Hevelius, my daughter, a tea tray
My 60th birthday just passed, and it made me think, oddly, of my daughter, a little-known constellation, an even more obscure astronomer and a tea tray.
Canes Venatici may be an obscure constellation, but it produces in me (in a convoluted way, as you shall see) an intensely religious frame of mind. Every time I look at it, I think of a time two decades ago, when my then four-year-old daughter rescued me from a terrible fate.
She was at her day-care center helping to take care of the pet gerbils. 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 Ursa Major (the Great Bear), part of which we commonly call the Big Dipper. 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.
All of Hevelius’s stellar observations were done without a telescope. Such was the sharpness of his eyes that the positions he plotted with simple sighting devices are just as precise as those done telescopically by the greatest observers of his age.
Hevelius was an artist as well as an astronomer. He lovingly engraved the star maps on copper plates, which were used to print the maps in 1690, three years after his death.
Hevelius’s charts are difficult to use for observing the stars. He engraved them as if they were positioned on a globe, so we see the constellations backwards, as if we were on the outside of the stars looking backward toward the Earth. He illustrated them with fanciful figures depicting the mythological characters represented by the constellations.
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 this telescope and others like it, Hevelius arduously made the most detailed lunar observations of his time. Like his star maps, those observations were lovingly recorded on copper plates for later publication. Only a few priceless copies of these moon and star maps remain. We would now consider the plates from which the maps were made important historical antiquities, but none of them survive. At least one of them was pounded into a tea tray.
We live in an age when the old is constantly pounded out to make the new. Beautiful old building falls to erect new ones. Irreplaceable 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. I am saddened beyond words at the thought of some unknown artisan pounding out the delicate contours of the lunar surface and intricate etchings 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.
Tom Burns is the director of Ohio Wesleyan University’s Perkins Observatory, and he would be very happy to answer your questions or sell you a ticket to one of its upcoming Friday-night programs. He can be reached at tlburns@owu.edu or 740–363-1257.
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