An experiment at once artistic and scientific, begun in 2018 at the Paris Observatory. Carried out with the researchers of the Syrte laboratory, it sets out to verify the difference between true solar time, which a sundial shows, and mean solar time, which a clock shows: where the meridian of true solar time is a straight line, that of mean time takes the shape of an elongated figure of eight.

For a year, every day at mean noon, Dallaporta made an exposure of the image of the sun entering the Cassini room of the observatory. Accumulated over the year, the exposures reveal that shape.