Continued from part 1.
Christoph Scheiner’s magnum opus is Rosa Ursina, published in 1620.
The title, roughly the Bear’s Rose, is an extremely poetic and sycophantic dedication to his patron, Virginio Orsini, Duke of Bracciano.
The bear, of course, is the patron’s name, and Scheiner waxes lyrical about the vast mind and infinite morality and radiant family of the bear. I think the rose is a metaphor for the sun, which is the main topic of the book. I can’t wade through the dense poetic Latin. The dedication to the reader has a different tone, comparing readers to crows who argue endlessly instead of getting shit done.
Most of the book is geometrical discussions of the earth’s orbit and sun angles. It includes diagrams and descriptions of the more complex equatorial scope with alidades and lenses, then a more basic semi-adjustable scope.
The simple scope (helioscopic machine) is meant as instructions for other DIY (fac per tibi) astronomers. I could have followed the instructions easily, though I’m perfectly unskilled at woodwork. A skilled carpenter could slap it together in a minute.
My model, with the relevant names attached:
Pes is the foot, suppedaneum is the underfoot thingie, dorsum is the back, tabella chartifera is the chart-holding table. Note especially the wingnut F! We don’t think of wingnuts in 1620. Webster says the earliest use in English is 1834. Scheiner doesn’t seem to mention it by name. His instructions don’t cover the telioscopia itself; he only advises you to get a bona telioscopia.
My version, shown on a table in the Brahe observatory:
The helioscopia wasn’t meant to be easily adjustable. The fulcrum had points at both ends so it was simply digging into the wood of the dorsum and the table, and had to be resituated for each angle.
Here’s a view through the telioscopia toward the sun. Poser doesn’t do refraction properly, so the image is just white.
Scheiner’s bobum plumba angle meter reminds me of a Maragha instrument that served the same purpose of sunspot observation.
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Language footnote: At this point in Latin orthography, the use of V and J was strictly typographical, not phonetic. We don’t know how the words sounded, but the distinction between fricative and semivowel was already established in Italian, so the “church” way of pronouncing Latin was probably normal by then. V was always used at the start of a word or in an all-caps title. J was only used at the end of words. Scheiner’s Latin is especially hard to read because he usually does the que suffix trick instead of putting et between words, and then abbreviates que as q with a period. He sometimes writes out et and sometimes uses ampersand. The q trick is especially silly because it doesn’t save any type compared to et, and uses more type than ampersand. Scheiner also uses the scribal abbreviations for nasals after vowels. The nasal may have already become part of the actual vowel as it did in French and Portuguese. The scribal overline became the tilde in writing.
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Happy Ending: Alidades disappeared from telescopes but remained very much alive in surveying equipment. Most of them are supplemented by lenses, but they’re still part of the device and still called alidades.
Polistra's Mill 