Carte Du Ciel - The Carte Du Ciel

The Carte Du Ciel

The still-more-ambitious Carte du Ciel component of the programme was undertaken by some of the participating observatories, but neither completed nor even started by others. The charts proved to be excessively expensive to photograph and reproduce, generally via engraved copper plates (photogravure), and many zones were either not completed or properly published. The plates which were taken generally still exist, but cover only half of the sky. They are typically archived at their original observatories. A very few plates have recently been re-measured and re-analysed with the availability of the Hipparcos Catalogue data (see below).