La conference sur la lumiere et l'astronomie a ete une occasion pour evoquer, notamment, l'observatoire astronomique d'Alger, cree au 19e siecle, et qui a pris part a de projets mondiaux d'envergure, tels que la conception de la carte du ciel
et l'operation d'etablissement des longitudes.
Its aim was to promote a project called the Carte du Ciel
('Map of the Sky').
At the turn of this century Europe's astronomers were preoccupied with the before-its-time, stupendous Carte du Ciel
star-mapping project - so much so that they missed the "Astrophysics Express" that was leaving the station.
By not participating in a major international project, the Carte du Ciel
photographic atlas and catalogue, American observatories were able to devote their assets to the development of astrophysics at a critical time in the evolution of that new discipline.
The second was a set of photographs charting the entire sky down to 14th magnitude, the Carte du Ciel