Construction of VLT main structure

The image shows the main structure of the VLT. It is the mechanical frame which holds the primary, secondary and tertiary mirrors aligned during the pointing and tracking of an astronomical object. The structure is composed of the fork (in blue) and the tube (silver). The fork turns around the vertical axis (azimuth), the tube turns around the axis passing through the shafts (altitude) which can be seen in the central square section (centrepiece). The photo was obtained at the Ansaldo factory in Milano (Italy) on October 10, 1996.