Masahiro Koishikawa#Discoveries

{{Short description|Japanese astronomer (1952–2020)}}

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class="wikitable floatright" style="font-size: 0.9em; width: 270px;" |+ Minor planets discovered: 19
see {{section link	List of discovered minor planets}}

{{Nihongo|Masahiro Koishikawa|小石川 正弘|Koishikawa Masahiro|1952 – 26 August 2020}} was a Japanese astronomer. He studied both major and minor planets, and discovered multiple asteroids.

Koishikawa was a staff member of the Sendai Astronomical Observatory frin 1972. His research was based out of the Sendai's Ayashi (391) station. The main-belt asteroid 6097 Koishikawa, discovered by Kin Endate and Kazuro Watanabe at Kitami in 1991, was named in his honor. He died on 26 August 2020 from lung cancer.[https://www.kahoku.co.jp/tohokunews/202008/20200828_13016.html 小石川正弘さん死去　仙台市天文台元職員　星空の魅力伝える] {{Webarchive|url=https://web.archive.org/web/20200828210124/https://www.kahoku.co.jp/tohokunews/202008/20200828_13016.html |date=2020-08-28 }} {{in lang|ja}}