I guess the actual date was yesterday. Ironically, the weather here has been May-like until yesterday, when it suddenly turned chilly again. Still, the hour has come when the warmer weather is sure to come.

So you know about Stonehenge, but here are five sites -- not all "ancient," in spite of the headline, in fact the majority Medieval -- built to align with the spring equinox. One of them is the Basilica San Petronio, which contains a feature that was used to help construct our modern calendar:
In 1575, cosmographer Egnazio Danti arrived in Bologna to teach mathematics and astronomy. In order to continue his work on the commission charged by Pope Gregory XIII with the development of a new calendar, he constructed a meridian line in San Petronia. The meridian line—an astronomical instrument invented by Danti—consisted of a small hole high on the wall of the church; the position of the spotlight created when the sun shined through the hole allowed Danti to define and analyze the sun’s position and movements. This technique was later used by Giovanni Cassini to confirm the elliptical orbital model proposed by Johannes Kepler.


douglas said...

One of the first purpose of architecture, after simple shelter, a marking the seasons. Funny how modern articles looking at these things think it's all about the ceremony or symbolism. They don't realize what it was like before watched, calendars (in the modern sense), and the pre-existence of the knowledge of what causes the seasons. You had to have something to mark the solar cycles, because your life depended on hunting and planting at the right time. The symbolism came because it was so important, not the other way 'round.

I also wish that article has better pictures, those don't show the actual aspect of the structure they were talking about, save for Chicken Itza. By the way, if you go there, be sure to see if they are still doing tours of the original pyramid. It's inside the current rendition, so you go deep, deep inside, and it's awesome (and really dark when they switch the lights off!). Go early, they don't do it later in the day because it's too hot then.

Many churches and main public squares in Europe have median lines and also sometimes things like standard measures (bars of certain lengths embedded in walls in Bergamo, Italy, for instance. No one pays any attention to this things now. At the Vatican, the obelisk is a gnomon for a giant sundial, though perhaps it's history is even more interesting.

douglas said...

Wow, proofreading, what a concept. But then we wouldn't have gems like "Chicken Itza"!

Grim said...

Yeah, I liked that one. :)