Palermo, district by district

Between 12 March and 19 April we concentrated on Palermo: all eight fixed points, on the moonless nights around the new moons of 19 March and 17 April, 56 sessions in all. Working close together in time means the weather and the season were about the same for every district, so the differences below come mostly from the ground.

The centre is not all one thing

Politeama, at 17.26, is the brightest point we measure anywhere. The meter stands at the edge of a wide square, with a floodlit theatre and shopfronts that stay lit all night. The Kalsa, about 1.5 km to the east, reads 0.42 darker. Its streets are narrow, its lamps are low, and one whole side of its sky faces the open sea.

The Zisa is the rooftop where this project started. Our first reading there, in March 2024, was 17.84. Two years later the spring median is 17.83. Nothing has changed that a meter can see.

Brancaccio surprised us

We expected the eastern district, with its ring road and warehouses, to read close to Politeama. It came in at 17.97, darker than the Zisa. Most of the lighting there is old, low and pointed at the ground, and the point is a long way from the floodlit centre.

What a mountain is worth

Mondello is only about ten kilometres from Politeama, but Monte Pellegrino stands between them. At 18.74 its sky is 3.9 times darker, even with a lit promenade at its back. Sferracavallo, further round the coast, gains another quarter of a magnitude. Boccadifalco, at the foot of the hills to the south-west, has no mountain in the way and reads 18.41.

The darkest point in the city, PA-08, is a lay-by on the road up Monte Pellegrino, about 400 m above the streets. It reads 19.27, and even there the glow of the whole city lies at your feet.

These are zenith readings. They describe the sky straight overhead, not the glow along the horizon. The full list of sessions is in the raw log, available on request.