Living inside a yurt, a round structure with a five foot, transparent, dome on the top, is just like living inside a giant calender.
This is a shot from before we moved our mountains of stuff if (obviously!) so you can see what I mean. The sun (or the moon, at night) shines through the dome, creating a perfect circle of light that travels across the floor like a spotlight. Today, on the summer solstice (actually, the Sun entered Cancer last night), this glowing circle is only a little off yurt-center at noon (off center owing to our latitude). If I put a mark there, it would show me, all year, how much further we had to go before summer.
Okay, now if you look at the picture, you can see the rafters, clocking around the round ceiling. There are fifty of them. Every day the sun comes up, shining that circle first onto the ceiling (before it gets high enough in the sky to hit the floor), and every day those first rays of light are a few inches over from the day before. As we move towards the solstice, each day the sunrise rays are a few inches south, about a rafter’s worth a week (52 weeks in the year, 50 rafters). Today is the zenith of this pattern. But in a few days, I’ll notice the sun-up rays (and sun-down rays on the other side of the yurt) will be a few inches north of their position today. As will be the location, at noon, of the light circle on the floor.
Every day, from now until the winter solstice, the sun circle will be a little closer to the wall until the angle of the sun is so low, it won’t it the floor at all, but move only across the wall. By winter solstice day, it won’t even hit the wall, but, at noon, will hover on the ceiling, just at the edge where the rafters connect to the wall. If I wanted to, I could mark that place, and know how much time had to pass before the beginning of winter. And I could mark the rafters with dates, and know, from where the sun circle came through in the morning, where exactly we were in the year. A giant, live-in, calender.
When I first heard about these places like Stonehenge, giant stones set up to catch the dawn light of the solstices, I couldn’t imagine the precision it would take to accomplish such a feat. But now, living in the yurt, I see that it isn’t that hard, at all. If those folk lived in one round room, it would be hard NOT to notice all of this, hard NOT to know exactly when and where the sun would be.
The hard part would be moving the rocks. I guess we got off easy.