Its not a sundial (which measure earth’s rotation), it’s a meridian line. I think they can be set up anywhere, but they’re measuring exact noon, and the light would “travel” north to south. It travels west to east, the line on the ground is oriented north/south. Lenny is facing north.
https://en.wikipedia.org/wiki/Palermo_Cathedral
“The device itself is quite simple: a tiny hole in one of the minor domes acts as pinhole camera, projecting an image of the sun onto the floor )” - It never specifically says west to east but that’s what’s it’s saying.
The sun seems to be coming from the right. In the northern hemisphere, the sun moves to the right from morning to evening, so the spot should mostly be moving towards the wall in the background, but as the sun also gets lower in the afternoon and evening, it should also be moving somewhat in the direction of the line.
I saw the sun more coming from the camera direction but I can see it coming from the right. Still it seems like it would miss the line, unless close to the equator
Depends on how things are oriented. If we’re looking south here then the sun would be to the west and the spot would travel toward the line as the sun got lower in the sky.
![But I need that point now [Medium]](https://lemmy.world/pictrs/image/f2e3e5ac-2a30-4d24-a029-5a7b247d91a3.jpeg){kind=link}
Correct me if I’m wrong but… wouldn’t the spot always be moving away from the line on the northern hemisphere?
As long as there are no mirrors involved I guess
Its not a sundial (which measure earth’s rotation), it’s a meridian line. I think they can be set up anywhere, but they’re measuring exact noon, and the
light would “travel” north to south.It travels west to east, the line on the ground is oriented north/south. Lenny is facing north.pauls-bologna.blog/2017/11/02/the-meridian-line-of-san-petronio/
It will travel north to south (and vice versa) throughout the year, but during the day
east to westwest to east surely.Shadow would move east to west, beam of light moves west to east.
Yeah the line on the floor is what’s North/South. The beam of light is moving west to east.
The beam of light moves the same way as a shadow would. Think of it as a “gap” in a shadow.
No it reverses it, the hole in the ceiling is creating a pinhole camera effect.
https://en.wikipedia.org/wiki/Pinhole_camera
https://en.wikipedia.org/wiki/Pinhole_camera#/media/File:Pinhole-camera.svg
https://en.wikipedia.org/wiki/Palermo_Cathedral “The device itself is quite simple: a tiny hole in one of the minor domes acts as pinhole camera, projecting an image of the sun onto the floor )” - It never specifically says west to east but that’s what’s it’s saying.
The pinhole effect reverses the image itself, but that is irrelevant. The beam of light will always travel west to east on the northern hemisphere.
The ‘image itself’ is the entire sky, which is being flipped.
The sun seems to be coming from the right. In the northern hemisphere, the sun moves to the right from morning to evening, so the spot should mostly be moving towards the wall in the background, but as the sun also gets lower in the afternoon and evening, it should also be moving somewhat in the direction of the line.
I saw the sun more coming from the camera direction but I can see it coming from the right. Still it seems like it would miss the line, unless close to the equator
Depends on how things are oriented. If we’re looking south here then the sun would be to the west and the spot would travel toward the line as the sun got lower in the sky.
The angle seems very steep for the sun to be in the west