K.K. Gotō Kōgaku Kenkyūjo (㈱五藤光学研究所) is a Japanese optical company, which has made telescopes and astronomical optical devices since its foundation and currently (2010) still exists. It made at least one camera lens in the early 1940s (see below).


The company was founded in 1926[1] by Gotō Seizō (五藤斎三), said to be a former employee of Nippon Kōgaku.[2] It sometimes used the Roman name Gotoh before World War II.[3] The company made the Triptar[4] lens mounted on the Miyako Six in 1942–3.

After the war, the company used the Roman name Goto or Goto Kogaku.[5] It made the first Japanese planetarium projector in 1958,[6] and still makes planetariums and telescopes. On May 21, 2004, the official English name of the company was changed from Goto Optical Mfg. Co. to Goto Inc.,[7] but the Japanese name was unchanged.


  1. Official company history in English and in Japanese.
  2. See this page about an old Gotō telescope.
  3. Advertisement reproduced in this page of the Old Telescope website.
  4. Name inferred from the katakana トリプター.
  5. See for example the products visible in this page.
  6. Company history at the Goto Inc. official English website.
  7. News release at Goto Inc.'s former English website (stored at


In English:

In Japanese: