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About The 188cm Telescope

The 188cm telescope

The 188cm telescope is the largest telescope in Japan. It was the seventh largest telescope in the world and the largest telescope in the eastern world at the time of its foundation. It took abount 5 years and cost 300 million dollers at the time to construct the telescope and its enclosure. This telescope has several sisters (i.e same type of telescopes construted by Grabb Persons Inc.) in the world; in Canada, in Australia, in France, in Egipt, and in South Africa.

Specifications

Basic spesifications

Latitude +34° 34′ 37.47” N
Longitude 133°35’38.24″ E
Altitude 372m
Telescope type Classical Type Cassegrain
(constructed by Grabb Persons Inc., UK in 1960)
Mounting British-type equatorially mounting
Weight 50t
Length 9m (center piece + octagonal torus)
Haltmann constant about 0.23
Pointing accuracy about 20 arcsec

Primary mirror

Focal length 9.15m F/4.9
Material Pylex
Thickness 27cm
Weight 1.7t
Surface shape Paraboloid

Secondary mirror(Material : fused quartz)

Diameter [mm] Weight [kg] Surface Paraaxial radius [mm]
Newton 533.4 41 Flat
Cassegrain 507.88 34 Hyperboloid 5937.50
Coude 507.88 34 Hyperboloid 5171.39

Focus

Focal length [m] Focal ratio Plate scale["/mm]
Newton 9.15 4.9 22.5
Cassegrain 33.85 18 6.09
Coude 54.29 29 3.80

Guide telescope

Diameter 15cm
Focal length 150cm
Field of view 1.18deg

Anecdote

The 188cm telescope impacted on people in Japan 46 years ago. A boy who saw some parts of the telescope being transported from Tamashima bay of Kurashiki city to Chikurin-ji mountain became an astronomer later, and he is still an active astronomer.