Re: still seems funny to me
"Watching the sun" is exactly what these stones were built to do. They had to be accurate (or accurate enough) and they had to be permanent in order to provide a known quantity.
The summer solstice wasn't really that important as summer was a time of bountiful supplies of food. Devices like Stone Henge were built to collect the timing of the winter solstice, for both an agricultural and a religious reason.
The agricultural reason was quite simple: they had to have a point from which to count the days until planting began. It was their farmer's almanac and set the seasonal calendar without reliance on the moon.
The religious reason was a little more esoteric. It was the fairly commonly held belief that the winter solstice was the time when life hung in the balance, and not merely in terms of the cold and shortening of food supplies. The days were getting shorter and shorter, the nights getting longer and longer, and there was a very palpable fear that the sun might just decide not to come back next year. They had to know with absolute certainty that the days were getting longer, and they had to know when that change began, in order to time the big week-long celebratory feast. Similar religious practices are found throughout Eurasia, especially in the more northerly areas, and defined much of the form and function of Christmas (and no, before anyone claims it, christianity didn't coopt the old religious practices to trick or ease pagans into converting: converts to the new religion simply carried on their old feasts with new names, to the great dismay of the religious leaders of the time).
This is all well-known and has been for some time. What this particular study has done is directly verify that which was already known from other sources.
Still won't convince all those nellies that thing Stone Henge was built to measure the summer solstice and use it as an excuse to dance around in their underpants, but what can you do?
And now back to my little Florentine adventure. Ho the Medici! I require more culturally attuned steak!