Japanese Star Globe

We do not know who made this globe, but a Chinese inscription on the sphere tells us that the object was crafted in Tenmei yonen saiji kinoetatsu gogatsu, that is, "the fifth month of the forth year of Tenmei" (Image 1). Tenmai is the name of an era in Japan spanning the period 1781-1789, so the sphere can be identified as Japanese and dated to 1784.

The globe is less ornamental than the majority of Asian astronomical instruments that survive from the Edo period (1603-1868), such as the Japanese sundial pictured in Image 2. Stars are inked onto the paper surface, rather than being engraved on a costly metal sphere, as they would have been on courtly globes. The small size, low weight, and clarity of the characters suggest that the globe might have been used in teaching - the item could be readily carried around and the characters are easy to read. Alternatively, the globe might have been a prototype for a more luxurious instrument.

While we tend to see astronomy as an observational science, astronomers in the Chinese tradition took a great interest in historical aspects of their subject. On the Japanese globe here, stars are inked in different colours (Image 3) to indicate in which of the three traditional Chinese jia, or "houses", of astronomy they were first recorded. Stars that can no longer be seen are also nevertheless recorded. The way that the stars are mapped on this globe suggests that the maker was interested in historically focused Chinese astronomy.

This article is based on the work of Hilary Smith, 'An Eighteenth Century Japanese Celestial Globe', submitted for the M.Phil Degree, 2000.

Katie Taylor

Katie Taylor, 'The Japanese star globe and historical astronomy', Explore Whipple Collections, Whipple Museum of the History of Science, University of Cambridge, 2009.

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