On August 25, the first 7-m antenna manufactured by Japan was transported to the Array Operations Site (AOS) at 5000 m asl from the Operations Support Facility (OSF) at 2900 m asl where the antenna evaluation test had been conducted. This is the fifth Japanese antenna that arrived at the AOS, following the four 12-m antennas which have already been in use for test observation. These Japanese antennas will be a part of the Atacama Compact Array (ACA) nicknamed “IZAYOI” consisting of four 12-m antennas and twelve 7-m antennas. The construction of the ACA is well under way toward the start of regular operation .

The first 7-m antenna was handed over to the Joint ALMA Observatory (JAO) on May 2, 2011, after the completion of adjustment and performance evaluation. The main reflector of the antenna demonstrates a very high surface accuracy with an error of just 4 μm from an ideal paraboloidal surface under the best conditions. The remaining eleven 7-m antennas are in the production or evaluation phase on schedule. For detailed information on the ACA 7-m antenna and its function in ALMA, please see
First Japanese 7-m Antenna Handed Over to JAO .

The first 7-m antenna being carried to the AOS by the transporter
[Photographed by Joaquin Collao (NAOJ)]

The first 7-m antenna installed at the AOS (second from right). Other three are 12-m antennas manufactured by Japan. [Credit: ALMA (ESO/NAOJ/NRAO), W.Garnier (ALMA)]