Astronomer
Hiroki Kosai
Japanese astronomer
1933 - 2026
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Hiroki Kosai
His biography is available in 20 different languages on Wikipedia (up from 19 in 2024). Hiroki Kosai is the 471st most popular astronomer (up from 481st in 2024), the 1,322nd most popular biography from Japan (up from 1,363rd in 2019) and the 6th most popular Japanese Astronomer.
Memorability Metrics
3.0k
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Past 12 months
56.26
HPI
Historical Popularity Index
Data Insights
#1 / 12
Hiroki Kosai is the most memorable of the 12 notable people born in Kurashiki, Japan, ahead of Kiichirō Furukawa, Naohito Fujiki, and Jinyu Nasu.
Page views of Hiroki Kosai by language
Among Astronomers
Among astronomers, Hiroki Kosai ranks 471 out of 663. Before him are Joel Stebbins, Milorad B. Protić, Bohdan Paczyński, Audouin Dollfus, William Wilson Morgan, and Hugo Gyldén. After him are Carolyn Porco, Elia Millosevich, Minoru Honda, Pierre Puiseux, Edward Pigott, and Lyudmila Karachkina.
Most Popular Astronomers in Wikipedia
Go to all RankingsJoel Stebbins
1878 - 1966
HPI: 56.41
Rank: 465
Milorad B. Protić
1911 - 2001
HPI: 56.40
Rank: 466
Bohdan Paczyński
1940 - 2007
HPI: 56.37
Rank: 467
Audouin Dollfus
1924 - 2010
HPI: 56.32
Rank: 468
William Wilson Morgan
1906 - 1994
HPI: 56.31
Rank: 469
Hugo Gyldén
1841 - 1896
HPI: 56.30
Rank: 470
Hiroki Kosai
1933 - 2026
HPI: 56.26
Rank: 471
Carolyn Porco
1953 - Present
HPI: 56.23
Rank: 472
Elia Millosevich
1848 - 1919
HPI: 56.21
Rank: 473
Minoru Honda
1913 - 1990
HPI: 56.20
Rank: 474
Pierre Puiseux
1855 - 1928
HPI: 56.19
Rank: 475
Edward Pigott
1753 - 1825
HPI: 56.18
Rank: 476
Lyudmila Karachkina
1948 - Present
HPI: 56.18
Rank: 477
Contemporaries
Among people born in 1933, Hiroki Kosai ranks 366. Before him are Maurinho, Miriam Stevenson, Nate Brooks, Reiner Kunze, Mark Forest, and Abdul Rahman Munif. After him are Mike Larrabee, Gino Pivatelli, Knut Johannesen, Georgi Burkov, Tatiana Doronina, and Wayne Rogers. Among people deceased in 2026, Hiroki Kosai ranks 200. Before him are Epeli Nailatikau, Yōhei Kōno, Robert Trivers, Ann Blyth, Robert Thurman, and Kazuo Imanishi. After him are Borislav Paravac, Ralph Towner, Boris Isachenko, Hans-Georg Reimann, Aleksandr Panayotov Aleksandrov, and Duane Michals.
Others Born in 1933
Go to all RankingsMaurinho
SOCCER PLAYER
1933 - 1995
HPI: 56.44
Rank: 360
Miriam Stevenson
CELEBRITY
1933 - Present
HPI: 56.40
Rank: 361
Nate Brooks
ATHLETE
1933 - 2020
HPI: 56.37
Rank: 362
Reiner Kunze
WRITER
1933 - Present
HPI: 56.35
Rank: 363
Mark Forest
ACTOR
1933 - 2022
HPI: 56.35
Rank: 364
Abdul Rahman Munif
WRITER
1933 - 2004
HPI: 56.33
Rank: 365
Hiroki Kosai
ASTRONOMER
1933 - 2026
HPI: 56.26
Rank: 366
Mike Larrabee
ATHLETE
1933 - 2003
HPI: 56.22
Rank: 367
Gino Pivatelli
SOCCER PLAYER
1933 - 2025
HPI: 56.15
Rank: 368
Knut Johannesen
SKATER
1933 - Present
HPI: 56.14
Rank: 369
Georgi Burkov
ACTOR
1933 - 1990
HPI: 56.11
Rank: 370
Tatiana Doronina
ACTOR
1933 - Present
HPI: 56.02
Rank: 371
Wayne Rogers
ACTOR
1933 - 2015
HPI: 56.02
Rank: 372
Others Deceased in 2026
Go to all RankingsEpeli Nailatikau
POLITICIAN
1941 - 2026
HPI: 56.49
Rank: 194
Yōhei Kōno
POLITICIAN
1937 - 2026
HPI: 56.45
Rank: 195
Robert Trivers
BIOLOGIST
1943 - 2026
HPI: 56.43
Rank: 196
Ann Blyth
ACTOR
1928 - 2026
HPI: 56.42
Rank: 197
Robert Thurman
WRITER
1941 - 2026
HPI: 56.39
Rank: 198
Kazuo Imanishi
SOCCER PLAYER
1941 - 2026
HPI: 56.34
Rank: 199
Hiroki Kosai
ASTRONOMER
1933 - 2026
HPI: 56.26
Rank: 200
Borislav Paravac
POLITICIAN
1943 - 2026
HPI: 56.26
Rank: 201
Ralph Towner
MUSICIAN
1940 - 2026
HPI: 56.23
Rank: 202
Boris Isachenko
ATHLETE
1958 - 2026
HPI: 56.22
Rank: 203
Hans-Georg Reimann
ATHLETE
1941 - 2026
HPI: 56.22
Rank: 204
Aleksandr Panayotov Aleksandrov
ASTRONAUT
1951 - 2026
HPI: 56.13
Rank: 205
Duane Michals
PHOTOGRAPHER
1932 - 2026
HPI: 56.13
Rank: 206
In Japan
Among people born in Japan, Hiroki Kosai ranks 1,322 out of 6,943. Before him are Prince Fushimi Hiroyasu (1875), Sion Sono (1961), Kimiko Shiratori (1968), Haruko Sugimura (1909), Masahiro Akimoto (1979), and Momoe Yamaguchi (1959). After him are Eijun Kiyokumo (1950), Takayuki Kubota (1934), Kappei Yamaguchi (1965), Takako Doi (1928), Masafumi Terada (1994), and Minoru Honda (1913).
Others born in Japan
Go to all RankingsPrince Fushimi Hiroyasu
MILITARY PERSONNEL
1875 - 1946
HPI: 56.28
Rank: 1,316
Sion Sono
FILM DIRECTOR
1961 - Present
HPI: 56.27
Rank: 1,317
Kimiko Shiratori
SOCCER PLAYER
1968 - Present
HPI: 56.27
Rank: 1,318
Haruko Sugimura
ACTOR
1909 - 1997
HPI: 56.27
Rank: 1,319
Masahiro Akimoto
SOCCER PLAYER
1979 - Present
HPI: 56.26
Rank: 1,320
Momoe Yamaguchi
ACTOR
1959 - Present
HPI: 56.26
Rank: 1,321
Hiroki Kosai
ASTRONOMER
1933 - 2026
HPI: 56.26
Rank: 1,322
Eijun Kiyokumo
SOCCER PLAYER
1950 - Present
HPI: 56.25
Rank: 1,323
Takayuki Kubota
MARTIAL ARTS
1934 - 2024
HPI: 56.24
Rank: 1,324
Kappei Yamaguchi
ACTOR
1965 - Present
HPI: 56.22
Rank: 1,325
Takako Doi
POLITICIAN
1928 - 2014
HPI: 56.21
Rank: 1,326
Masafumi Terada
SOCCER PLAYER
1994 - Present
HPI: 56.21
Rank: 1,327
Minoru Honda
ASTRONOMER
1913 - 1990
HPI: 56.20
Rank: 1,328
Among Astronomers In Japan
Among astronomers born in Japan, Hiroki Kosai ranks 6. Before him are Takeshi Urata (1947), Tsutomu Seki (1930), Chushiro Hayashi (1920), Kiyotsugu Hirayama (1874), and Hisashi Kimura (1870). After him are Minoru Honda (1913), Kaoru Ikeya (1943), Okuro Oikawa (1896), Hiroshi Kaneda (1953), Yuji Hyakutake (1950), and Kiichirō Furukawa (1929).
Takeshi Urata
1947 - 2012
HPI: 59.73
Rank: 1
Tsutomu Seki
1930 - Present
HPI: 58.40
Rank: 2
Chushiro Hayashi
1920 - 2010
HPI: 58.08
Rank: 3
Kiyotsugu Hirayama
1874 - 1943
HPI: 58.04
Rank: 4
Hisashi Kimura
1870 - 1943
HPI: 56.71
Rank: 5
Hiroki Kosai
1933 - 2026
HPI: 56.26
Rank: 6
Minoru Honda
1913 - 1990
HPI: 56.20
Rank: 7
Kaoru Ikeya
1943 - Present
HPI: 55.83
Rank: 8
Okuro Oikawa
1896 - 1970
HPI: 55.09
Rank: 9
Hiroshi Kaneda
1953 - Present
HPI: 55.07
Rank: 10
Yuji Hyakutake
1950 - 2002
HPI: 54.93
Rank: 11
Kiichirō Furukawa
1929 - 2016
HPI: 54.62
Rank: 12

























































