Seven Buildings in Mitaka Campus become as Registered Tangible Cultural Properties
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On November 15, 2013, the report of the registration to tangible cultural properties of seven buildings in Mitaka campus (the headquarters) of National Astronomical Observatory of Japan (NAOJ) was submitted to Minister of Education, Culture, Sports, Science and Technology (MEXT) by the Council for Cultural Affairs of Agency for Cultural Affairs.
The seven buildings are 1) Housing of Repsold Transit Instrument, 2) Housing of Gautier Meridian Circle, 3) First Meridian Mark Building, 4) Second Meridian Mark Building, 5) Old Library and its Warehouse (Old Library), 6) Gatehouse, and 7) Front Gate. These are valuable as cultural properties that should be preserved as modern architecture of from Taisho era to early Showa era. In the Mitaka campus of NAOJ, three buildings are already become as registered tangible cultural properties that are Spectroheliograph Tower (Solar Tower Telescope/Einstein Tower), 65cm Telescope Dome, and 20cm Telescope Dome. Including those new registered buildings, the number of registered tangible cultural properties in Mitaka campus becomes ten.
Housing of Repsold Transit Instrument
The Housing of Repsold Transit Instrument, the completion date of it is February 28, 1925 (14 year of the Taisho era). This is a flat building made with reinforced concrete. It has East-West open-close roof, and the building is East-West symmetry. The top side of the building was decorated with the secession style, and it has beautiful exterior. The observational use of Repsold Transit Instrument finished in end of 1950s. After that, the housing of Repsold Transit Instrument has been opened to public as a NAOJ Transit Instruments Museum since 2008. Also, the Repsold Transit Instrument was designated as a national important cultural property in June 2011. The preserved condition is good and the open-close system of the roof is also existing. It almost remains the status of construction at the time.

Housing of Gautier Meridian Circle
The housing of Gautier Meridian Circle was completed on May 9, 1924 (13 year of the Taisho era). The shape of building is really characteristic as a telescope dome. It is semi-circle dome shape and the roof is East-West side open-close style. The Facilities Department of Tokyo Imperial University designed it. Moreover, there are meridian mark building in the point of 100m in North and South as attached facilities of the Gautier Meridian Circle to collimate the true North-South. This was built when the observatory moved from Azabu to Mitaka. According to the age, the background, and the design of building, it is said that the building is representative of Taisho era observational facilities existing in Mitaka campus.

First Meridian Mark Building of Gautier Meridian Circle
The completion date of the First Meridian Mark Building is February 28, 1925 (14 year of the Taisho era). It is the building for setting the collimation point at the 100m to South horizontally from fixed point of the Gautier Meridian Circle. The structure is two-story made with reinforced concrete. The pier which the meridian mark sits on is independent from the building and it goes through two floors. There is land elevation covered south side of the building for making temperature change smaller. Now, it is buried in deep forest.
Second Meridian Mark of Gautier Meridian Circle
The completion date of the Second Meridian Mark Building is February 28, 1925 (14 year of the Taisho era). It is the building for setting the collimation point at the 100m to North horizontally from fixed point of the Gautier Meridian Circle. the structure is two-story made with reinforced concrete. The pier which the meridian mark sits on is independent from the building and it goes through two floors. There is land elevation covered north side of the building for making temperature change smaller. Now, it is buried in bamboo and shrubs.

Old Library and its Warehouse
This was completed on March 31, 1930 (5 year of the Showa era). This is two-story building made with reinforced concrete and using Ohya stone pitching. The walls are embellished with scratch tiles. Three-story building which was designed in original drawing of construction was initially described as expansion plans, and it was built at west side of the library with mortar finish of the exterior wall on March 31, 1961 (36 year of the Showa era).

Gatehouse
The completion date of the Guard House is December 22, 1924 (13 year of the Taisho era). This is only one wooden western-style architecture existing in Mitaka campus. It is flat building with using Ohya stone to the base. The roof is a gable roof covered with color steel sheet. The exterior wall is western-style clapboard siding with narrow width in small pitch, and column shapes are attached to the wall like half timbering. In Mitaka city, there are eight modern architecture buildings (NAOJ’s building not included), and only three of them are Taisho era buildings. This is one of the valuable western-style architecture.

Front Gate
The detail date of completion of the Front Gate is unknown, but it is thought that built almost same time of the Guard House which was completed in 1924 (13 year of the Taisho era). In present condition, the gate door was updated from wooden to iron in 1993 (5 year of the Heisei era), but the gatepost made with Ohya stone, the mound and etc. are kept condition of the time of construction. This is the valuable building to tell the history of NAOJ. It is the basing point for welcoming visiting people who come to look the historical buildings of the green rich observatory.
