On March 2, 2010, the ALMA-Japan Antenna Nickname Selection Committee (chaired by Leiji Matsumoto) nicknamed the Japanese ALMA antennas "IZAYOI" after considerable discussions.

Selected nickname: IZAYOI

Points for selection:

• It has a meaning related to the number of the Japanese antennas "16".
• It evokes the images of "night sky," "astronomy," and "universe."
• It is a beautiful, classical Japanese word.

The campaign to nickname the Japanese ALMA antennas targeted young people aged 18 or younger. The purpose of the campaign is to foster a sense of affinity among children by offering an opportunity to nickname the Japanese ALMA antennas, which will be operated for the next 30 years.

The selection committee invited the ideas for a nickname from December 8, 2009 to February 14, 2010 and received 1829 submissions. The nickname "IZAYOI" was proposed by 28 people, which was the second largest number of submissions. ALMA consists of 66 or more antennas in total, and Japan is responsible for the development and manufacture of 16 antennas. "IZAYOI" is a classical Japanese word which means the moon on the 16th day or on the 16th night in the lunar calendar. While the moon on the 15th day is a full moon, the moon on the 16th day is a moon slightly waning.

Link

More info: ALMA web page