History

In early Japanese history, astronomical observations were sporadic and limited in scope. The first continuous, methodical celestial observations began in 1782 at Asakusa Observatory through the work of the Tenmonkata (Official Astronomer) under the direction of the Shogun in the latter part of the Edo era. In the Meiji era, an observatory for student observations was established in Hongo Campus of the University of Tokyo, and the Tokyo Astronomical Observatory was established in Azabu, Minato-ku, in 1888 (Meiji era 21*). The astronomical observatory was moved to Mitaka in 1924 (Taisho era 13).

In the beginning, the main task of the astronomical observatory was to observe the stars in order to determine longitude and latitude, calculate the calendar, and determine the correct time. These were started as national projects in the Meiji era, and our observatory continues to fulfill these functions to this day.

In 1988 (Showa era 63), the Tokyo Astronomical Observatory was reorganized into the National Astronomical Observatory of Japan, together with the Latitude Observatory in Mizusawa and others. For a time the observatory was under the jurisdiction of the Ministry of Education, Science, Sports and Culture (the Ministry of Education) which was reorganized to be the Ministry of Education, Culture, Sports, Sciences and Technology (MEXT). Finally the National Astronomical Observatory of Japan (NAOJ) was incorporated as the Inter-University Research Institute Corporation, National Institutes of Natural Sciences, National Astronomical Observatory of Japan on April 1, 2004.

*Note: In addition to the standard Gregorian Calendar, Japan continues to use a reign era calendar. The different eras are defined by changes in the Japanese government, and accompanied by changes in Japanese society.

Brief History
Year	Event
June 1888 (Meiji era 21)	The Tokyo Astronomical Observatory was established. (IIkura, Azabu)
September 1899 (Meiji era 32)	The Latitude Observatory was established in Mizusawa.
March 1909 (Meiji era 42)	Land was bought in Mitaka.
1914 (Taisho era 3)	Construction for Mitaka Campus started.
1916 (Taisho era 5)	Mitaka Main Building broke ground.
1920 (Taisho era 9)	Solar Photographic Building was completed.
1920 (Taisho era 9)	20-cm Telescope Dome was completed.
1921 (Taisho era 10)	Mitaka Main Building was completed.
February 1925 (Taisho era 14)	Publication of the “Rikanenpyo: Chronological Scientific Tables” began.
1926 (Taisho era 15)	65-cm Telescope Dome was completed.
November 1929 (Showa era 4)	65-cm Refractor Telescope was established.
February 1930 (Showa era 5)	Solar Spectroscopy Photographic Building (The Solar Tower Telescope) was built.
January, 1946 (Showa era 21)	Publication of [Almanacs and] “Calendar and Ephemeris” began.
1949 (Showa era 24)	Norikura Solar Observatory began observations. (Opening ceremony held in July 1950.)
1960 (Showa era 35)	Okayama Astrophysical Observatory began observations. (91-cm Reflector Telescope test observations conducted in April. 188-cm Reflector Telescope observations started in November.)
December, 1962 (Showa era 37)	Dodaira Observatory began observations. (Opening ceremony held on November 1.)
1969 (Showa era 44)	Nobeyama Solar Radio Observatory began observations. (Opening ceremony held on October 9.)
1982 (Showa era 57)	Nobeyama 45-m Radio Telescope began observations. (Opening ceremony of Nobeyama Radio Observatory held on March 1.)
July 1, 1988 (Showa era 63)	The National Astronomical Observatory of Japan was established.
1992 (Heisei era 4)	Nobeyama Radioheliograph began observations.
June 23, 1998 (Heisei era 10)	The Solar Tower Telescope (The Einstein Tower) was registered as a Tangible Cultural Property of Japan.
January 1999 (Heisei era 11)	The Subaru Telescope achieved first light. (Completion ceremony held on September 17.)
August 6, 1999 (Heisei era 11)	Laser Interferometer Gravitational Wave Antenna “TAMA300” began observations.
March 2000 (Heisei era 12)	Dodaira Observatory was closed.
July 20, 2000 (Heisei era 12)	Visitor’s Area of Mitaka Campus opened to the public.
April 5-6, 2001 (Heisei era 13)	NAOJ, the European Southern Observatory and the National Science Foundation (of the U.S.A.) agreed on the plan for ALMA.
February 14, 2002 (Heisei era 14)	20-cm Telescope Dome and 65-cm Telescope Dome (Observatory History Museum) were registered as Tangible Cultural Properties of Japan.
April 1, 2004 (Heisei era 16)	NAOJ was incorporated as the National Astronomical Observatory of Japan, National Institutes of Natural Sciences, Inter-University Research Institute Corporation.
June 27, 2011 (Heisei era 23)	The Repsold Transit Instrument was registered as an Important Cultural Property of Japan.
2011 (Heisei era 23)	Initial ALMA operations started.
2014 (Heisei era 26)	Repsold Transit Instrument Housing, Gautier Meridian Circle Housing, First Meridian Mark Building of the Gautier Meridian Circle, Second Meridian Mark Building of the Gautier Meridian Circle, Old Library and its Storehouse, Gate House, and Front Gate of NAOJ were registered as Tangible Cultural Properties of Japan.