徳川吉宗の一閑張大望遠鏡

抄録

We investigated the two long ikanbari telescopes, one is a private collection in Nagasaki and another is owned by the Kobe city museum, with special interest on the traditional technique of ikanbari telescope tube. As a result, both telescopes were produced by Hirai Ikan Sen'oshi family, and presented to the eighth shogun Yoshimune Tokugawa as a pair of telescope. Those two telescopes are the frst astronomical telescope produced in Japan.