A fragment of this amazing image by Alfred Lee that is today’s NASA Astronomy Picture of The Day. It reminded me of how AlHazen (11th century) figured out the principle of the camera obscura by observing the shape of light patches produced during solar eclipses. If I remember well, Roger Bacon (13th century) wrote about the crescent-shaped patches of light that can be observed on the ground in a forest during a solar eclipse. This is an modern, urban version of that observation: eclipses projected by a sky-scraper; take a look at the original picture of which this is a detail !