MM6.5III

Turnshek85 standard: RU Her - M6.5III
Keenan89 standard:   tet Aps (=HD 122250) - M6.5III:

# Standards

tet Aps = HD 122250 (J1405-7647; V~6)
 
RU Her = IRC +30283
   M6e: Keenan66(1966/Jul/22;V=7.1;near max)
   M6.5III: Turnshek85(stan)
   M7: Pesch67
   M7e: Keenan74(1967/Apr/11;V=8.2)
   M9: Wycoff73(1972/Apr/3;V=14.0), Solf78(1972/Mar/6;V=7.5)
   M7/10: Wisniewski67

   Extremely variable and spectral type changes over time.