B3IV JM53, Garrison67, MK73, & Houk88 do not list a B3IV standard MK43 standard: iot Her - B3IV sig Sgr - B3IV-V MK78 standard: iot Her - B3IV Mv(B3IV) = -2.3 ; GrayCorbally09 # Primary standard HD 160762 = iot Her B3V: JM53,Cowley72(stan),Jaschek64(most) *B3IV: MK43,Lesh68,MK78 B3: Cannon,Neubauer43 JM53 noted "SB". Consistently B3. Best considered "B3IV" standard (MK78).