Construction of a holography tower has started in the area 300 meters away from the assembly sites of the Japanese and North American antennas at the OSF. The 50-meter high holography tower is used to transmit reference signals for accuracy measurement of the main reflector panels of both Japanese and North American antennas. The picture shows a concrete foundation block for the tower and a hole to bury it in. You can see in the back the temporary building to support assembly, integration and verification activities.