Solstice in Rome

Since June 21 was the solstice, I went to a nearby church – Santa Maria degli Angeli that has a meridian line on the floor. I think that I talked about the meridian line in the Bologna Duomo before. It is an astronomical tool that Pope Gregory used when he was fixing the length of the solar year, and thereby fixing the calendar. This meridian line is a copy of the one in Bologna, not installed until the early 18th century. There is a book written about these cathedrals called The Sun in the Church: Cathedrals as Solar Observatories by J. L. Heilbron.

The line traces out the location of "High Noon" or solar noon on the church’s floor. Because the sun gets higher in the sky in summer and lower in the sky in winter, the line is quite long at this latitude. At one end of the line you have the summer solstice, and the form of Cancer – the crab, the astrological symbol for this time of year. At the other end you have Capricorn – a goat. (By coincidence, my sign is Cancer and Doreen’s is Capricorn. We just can get any different, can we?) You have the other signs of the zodiac up and down the line, in order of their appearance in the year. This is the line that we talk about when using the terms "AM" and "PM" the sun is "Before the Line" Ante Meridian – in the morning, and "After the Line" or Post Meridian in the afternoon.

You can see the pediment blocking the sun beam.

This little church is the one built into the old Baths of Diocletian. Michaelangelo helped with the conversion, but you cannot see much of his work left. The place has been renovated so many times (as recently as the 1970s) that not much of the original soul of the place is left. It is a haunting, sad church, with too many 19th century "wedding cake" additions to make it comfortable.

Looking UP at the sun beam coming through the cut in the details

Those 19th century, "renovations" rendered the meridian line unusable (They put in some useless pediment and cornices that blocked the "sun hole" The "star hole" was completely covered over, making the stellar part of the observatory useless) Later a wedge was cut out of the pediment that blocked the light. Just a thin wedge, but it did allow the light through. In addition to the sun hole, the south wall has some clear windows that cast sunbeams on the floor as well. These cannot be used with the meridian line.

I was not sure what "sun time" is here in Rome, so I got to the church around 12:10 PM (they have daylight savings time here, too) and was accosted by gypsies as I tried to enter the church. Three women and some babies and children started begging and grabbing at me as I pass by the doors. I shook them off (probably more violently that I should have, but I hate it when beggars grab hold of me) and entered the church.

As I was waiting patiently in church (I don't do waiting patiently very well. I did not have a book with me either, but I thought that I would take this opportunity for some quiet contemplation) several groups of tourists entered, and the tour guide took them to the line. One group even came and took pictures of the sun spot created from the windows crossing the line. I told one fellow that was not the real marker, he smiled, nodded, told me he knew that, then took a picture of the sun crossing the line (where it would cross in October) and left. It was very odd.

The "wrong" sun spots

I was not sure if the cut in the pediment was deep enough to let the sun in on the solstice, but I waited and waited. Around 12:50 another group came in who obviously knew what was going on. At the same time, a film crew started setting up around the meridian line. One of the people who knew what was happening was a local astronomy professor. I could understand a bit of his Italian, but asked him in English what time it would cross the line. He said around 1:12, and the he said, well, 1:11:47 exactly. It was fun chatting with him as we waited. He showed us the brass mark on the crab (Cancer, of course) mosaic where the tip of the spot would touch as it crossed the line.

The "right" sun spot

At 12:55 the spot came into view, and the film crew started filming its motion across the floor. It is surprising how fast it moved across the floor and onto the mosaic. We all watched, and it crossed exactly where predicted (I was thankful that the floor wasn't ripped up during one of the renovations). It disappeared behind another piece of decoration about 1:15, so it was a very short transit.

High Noon on the Solstice!

It was a fun experience.

RETURN TO THE GRAND TOUR HOMEPAGE!

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