A3III HR 3514 is the best A3III standard (southernly accessible also). MK43 standard: gam UMi - A3III [in text, A3II-III on plates] JM53 standard: bet Eri - A3III tet Gem - A3III Cowley69 standard: tet Gem - A3III Houk standard: bet Eri - A3III [from JM53] Jacoby84 star: HD 12027 - A3III GrayGarrison89 standard: HR 3514 - A3III(low vsini) (J-H)(A3III) = 0.029 ; smoothed relation from giants in Skiff compnedium w/i 15 deg of NGP, 2MASS photometry AAA flags (H-Ks)(A3III) = 0.025 ; smoothed relation from giants in Skiff compnedium w/i 15 deg of NGP, 2MASS photometry AAA flags => adopt (J-H)(A3III) = 0.029 [updated 10/30/2020] => adopt (H-Ks)(A3III) = 0.025 [updated 10/30/2020] # No standards GrayGarrison89 list a low vsini standard, but no high vsini standard. # Primary Standards HR 3514 = HD 75630 = HIP 43325 (J0849-4019; V=5.5) A3III:GrayGarrison87(low vsini stan.) A2: Cannon SMARTS 1.5-m spectrum in hand, blue (26Ia) and red (47Ib). # Weak standards tet Gem = HR 2540 = HD 50019 (J0652+3357; V=3.6) A3III: JM53,Osawa59,Jaschek64(most) A3III-IV: GrayGarrison89 A3V: Maury1897 A2I: vanDien49 A2IV: Abt95 A2.5IV: Palmer68 A5III: Chalonge52 B8Ib-II: Bouw81 bet Eri = HD 33111 = HR 1666 (J0507-0505, V=2.8) A3IV: Gray03 A3IVn: GrayGarrison89(high-vsini stan.) A3III: JM53,Abt95,Levato72 A3V: Levato78,Palmer68 A2IV: Bouw81 Good agreement on "A3" temperature type. I adopt the GrayGarrison89 luminosity class, so "A3IVn" it is. HD 12027 = TYC 2816-709-1 (J0158+3741; V=8.3) A3III: Kennedy83(Rebeirot70),Jacoby84 Too faint for Hipparcos. The original A3III type comes from Rebeirot70 (I'm , and was adopted by Kennedy83 and Jacoby84. That is probably not a strong enough pedigree to consider it a standard. I couldn't find a discussion on the sources of the spectral types in the Rebeirot70 paper, nor against which standards the A3III was typed from.