Duba wurin da ke ƙasa sannan ka amsa tambayar daga baya a cikin harshe ɗaya kamar yadda wurin yake:  Passage: Ka'idojin "anchor" waɗanda ke bayyana grid na rarrabuwa na MK don taurari na O-type, watau waɗancan ƙa'idodin waɗanda ba su canza ba tun farkon ƙarni na 20, sune 15 Monocerotis (O7 V) da 10 Lacertae (O9 V). The Morgan<unk>Keenan<unk>Kellerman (MKK) "Yerkes" atlas daga 1943 ya lissafa ƙa'idodin nau'in O tsakanin O5 da O9, amma kawai rarraba azuzuwan haske don O9s. Matsayi biyu na MKK O9 V sune Iota Orionis da 10 Lacertae. Sharuɗɗan Yerkes da aka sake dubawa ("MK") da aka gabatar a cikin Johnson & Morgan (1953) ba su gabatar da canje-canje ga nau'ikan O5 zuwa O8 ba, kuma sun lissafa ƙa'idodin 5 O9 V (HD 46202, HD 52266, HD 57682, 14 Cephei, 10 Lacertae) da ƙa'idodin 3 O9.5 V (HD 34078, Sigma Orionis, Zeta Ophiuchi). Wani muhimmin bita game da rarrabuwa na bakan gizo ta Morgan & Keenan (1973) ya lissafa ƙa'idodin "MK" da aka sake dubawa don O4 zuwa O7, amma kuma babu rarraba ƙa'idodi ta azuzuwan haske. Wannan bita kuma ya lissafa manyan jerin "ma'aunin dagger" na O9 V don 10 Lacertae da O9.5 V don Sigma Orionis.  Tambaya: Don me aka yi amfani da Iota Orionis da Lacartae 10?
MKK O9 V