O7III The best standard (southernly or otherwise) for O7III is HD 93222 Walborn73 standard: HD 93222 - O7III((f)) Garrison77 standard: xi Per Walborn90 standard: HD 93222 - O7III((f)) # No standard Hiltner69 does not list a O7III standard. # Primary standard HD 93222 (J1044-6005; V=8.1) *O7III((f)): Walborn71,Walborn73,Walborn90 O7: Morgan55 O8III((f)): Massey01 O8: Houk75 # Weak standard xi Per = HD 24912 (J0358+3547; V=4.0) *O7.5III(n)((f)): Walborn73 O7.5III(f): Bisiachi76 O7.5III: Bisiachi82 O7.5III(f): Mathys89 O7.5I: Conti71 O7.5: Lesh68 O7III: Garrison77(standard) O7I: Herrero92 O7: : Voroshilov85 O7: MK43,Berger55 O8III: Williams36 O9: Cannon