lambda Ori 3.    6.6    5.8-  7.5 0.52  8.05 0.12a HD catalogue, Cat. <III/135>
NGC 6530   2.    5.5    4.9-  6.1 0.84 10.76 0.33a Walker (1957ApJ...125..636W)
NGC 2264   3.    5.5    2.4-  6.0 0.06  9.24 0.05  Walker (1956ApJS....2..365W)
ONC        3.    5.0    2.8-  5.2 0.10  7.92 0.03  Brun (1935POLyo...1...12B)
sigma Ori  3.    0.4 <  6.6       0.26  7.98 0.06b HD catalogue, Cat. <III/135>
NGC 2362   4.5   9.1    5.4- 12.  0.08 10.71 0.08  Johnson (1950ApJ...112..240J)
Cep OB3b   4.5  10.     8.6- 10.9 0.05  8.72 0.89a Blaauw et al. (1959ApJ...130...69B)
IC 2602   25.   44.    28. - 62.  0.27  5.88 0.02  HD catalogue, Cat. <III/135>
NGC 2547  38.   48.    27. - 62.  0.13  8.03 0.04  Claria (1982A&AS...47..323C)
Pleiades       115.   104. -117.  0.81  5.35 0.02a Hertzsprung (1947AnLei..19a...1H)