Hiroki Kosai

Hiroki Kosai, born on February 8, 1933, was a prominent Japanese astronomer associated with the Kiso Observatory. His passion for astronomy not only fueled his own research but also played a significant role in popularizing the field across Japan.

Throughout his illustrious career, Kosai made remarkable contributions to the study of celestial bodies. He is particularly renowned for his observations of comets and asteroids, with one of his most notable achievements being the co-discovery of the comet 1976 XVI.

In addition to his work on comets, Kosai is credited by the Minor Planet Center with the discovery of nearly one hundred asteroids, showcasing his dedication and expertise in the field of astronomy.

Hiroki Kosai passed away on March 26, 2026, leaving behind a legacy that continues to inspire future generations of astronomers.