The table of Anchor Points for the MK System is taken from a paper by the author in the book "The MK Process at 50 Years," edited by Corbally, Gray and Garrison (ASP Conference Series, vol 60, 1994), pp. 3-14.

The "Anchor Points" is the subset of standard stars which have survived through the years with no change and which therefore represent the most stable points in the System. They do not form a complete grid. I am working on defining the set of "Primary Standards" which are the best current standards to use in terms of accessibility and suitability and which will represent a complete grid.

The first three columns in the table are self-explanatory. Column four is a list of classifications from the tables in the introductory booklet of the MKK Atlas (Morgan, Keenan, and Kellman, 1943). In parentheses are listed types from the Atlas which were not listed in the tables (only one star in this subset: HR 617), or which differed slightly from the types in the tables (only one star in the final list: HR 5191 and the only difference is that an "n" was added in the Atlas).

Column five is a list of classifications from Morgan's table of MK standard stars given in the UBV definition paper by Johnson and Morgan (1953). The types in the parentheses are from Michigan Publications No. X (1951).

Column six is a list of types from the 1973 Annual Reviews in Astronomy and Astrophysics article by Morgan and Keenan.

The types listed on the second page are taken from several modern lists. The second and third columns include types for stars cooler than the Sun, from various publications by Keenan and his associates. The fourth column includes types for GK stars by Morgan from an unpublished list as well as Walborn's (1973) types for O stars and Gray's (1986, 1989a,b, and 1994) types for B8-F2 stars.

Finally, all the types were checked for consistency with my own plate file. Thus, the Anchor Points represent the MK System as it was in 1943, as it was in 1953, 1973, 1978, 1989, and as it is now. The Anchor Points are the de facto standards, though they may not be the best ones or the ones we wish were standards. However, because of its long history, the MK System now has a life of its own. Instead of trying to manipulate it and distort it, we must listen to it.


  HD     HR or    Star        MKK43 Table    MK53 Table 1     MK73 Table 1,2
	 other    Name         (Atlas)       (Michpub1951)    (K76M78 Atlases)

 47839  HR 2456 15 S Mon        O7              (07)            07 (V)
214680  HR 8622 10 Lac          09 V            09 V            09 V
 36512  HR 1855 upsilon Ori     BO V            BO V            BO V
 37128  HR 1903 epsilon Ori     BO I            BO Ia           BO Ia (BO Ia)
 41117  HR 2135 chi-2 Ori       B2 I            B2 Ia           B2 Ia (B2 Ia)
206165  HR 8279 9 Cep           B2 I            B2 Ib           (B2 Ib)
120315  HR 5191 eta UMa         B3 V(n)         B3 V            B3 V
 32630  HR 1641 eta Aur         B3 V            B3 V            B3 V
 53138  HR 2653 omicron2 CMa    B3 I            B3 Ia           B3 Ia (B3 Iab)
 58350  HR 2827 eta CMa         B5 I            B5 Ia           B5 Ia (B5 Ia)
 34085  HR 1713 beta Ori        B8 Ia           B8 Ia           B8 Ia
103287  HR 4554 gamma UMa       AO V            AO V            AO V
172167  HR 7001 alpha Lyr       AO V            AO V            AO V (AO Va)
 87737  HR 3975 eta Leo         AO Ib           AO Ib           (AO Ib)
 21389  HR 1040 +58 607         AO Ia           AO Ia           (AO Ia)
197345  HR 7924 alpha Cyg       A2 Ia           A2 Ia           A2 Ia (A2 Ia)
216956  HR 8728 alpha PsA       A3 V            A3 V            A3 V
 89025  HR 4031 zeta Leo        FO III          FO III          FO III (FO III)
 36673  HR 1865 alpha Lep       FO Ib           FO Ib           FO Ib (FO Ib)
113139  HR 4931 78 UMa          F2 V            F2 V            F2 V (F2 V)
 20902  HR 1017 alpha Per       F5 Ib           F5 Ib           F5 Ib (F5 Ib)
 30652  HP 1543 pi-3 Ori        F6 V            F6 V            F6 V
194093  HR 7796 gamma Cyg       F8 Ib           F8 Ib           (F8 Ib)(WWM)
 54605  HR 2693 delta CMa       F8 la           F8 Ia           (F8 Ia)(WWM)
109358  HR 4785 beta CVn        GO V            GO V            GO V (PCK)
121370  HR 5235 eta Boo         GO IV           GO IV           (GO IV)(PCK)
204867  HR 8232 beta Aqr        GO Ib           GO Ib           GO Ib(PCK) (GO Ib)
   Sun  Sun     ASTEROIDS                       G2 V            G2 V
 20630  HR 996  kappa Cet       G5 V            G5 V            (G5 V)
161797  HR 6623 mu Her          G5 IV           G5 IV           G5 IV(G5 IV) note
206859  HR 8313 9 Peg           G5 Ib           G5 Ib           G5 Ib
101501  HR 4496 61 UMa          G8 V            G8 V            (G8 V)
188512  HR 7602 beta Aql        G8 IV           G8 IV           G8 IV
 62345  HR 2985 kappa Gem       G8 III          G8 III          G8 IIIa
113226  HR 4932 epsilon Vir     G8 III          (G8III)         G8 IIIab (G8 III)
 48329  HR 2473 epsilon Gem     G8 Ib           G8 Ib           G8 Ib
185144  HR 7462 sigma Dra       KO V            KO V            KO V
 62509  HR 2990 beta Gem        KO III          K0 III          KO IIIb
197989  HR 7949 epsilon Cyg     KO III          K0 III          KO- III
222404  HR 8974 gamma Cep       K1 IV           K1 IV           K1 IV  see notes
 22049  HR 1084 epsilon Eri     K2 V            K2 V            (K2 V)
 12929  HR 617  alpha Ari       (K2III)         K2 III          K2 IIIab
153210  HR 6299 kappa Oph       K2 III          K2 III          K2 III
127665  HR 5429 rho Boo         K3 III          K3 III          K3 III
 31398  HR 1577 iota Aur        K3 II           K3 II           K3 II
201091  HR 8085 61 Cyg A        K5 V            K5 V            K5 V
164058  HR 6705 gamma Dra       K5 III          K5 III          K5 III
  6860  HR 337  beta And        M0 III          M0 III          M0 IIIa
  1013  HR 45   chi Peg         M2 III          M2 III          M2+ III(M2 III)
 39801  HR 2061 alpha Ori       M2 Ib           M2 Iab          M1-M2 Ia-Ib
206936  HR 8316 mu Cep          M2 Ia           M2 Ia           M2 Ia

  HD     KY88         KY85               WWM GK STD 86
	(KM89)       (KP80)           Walborn OB, GRAY BAF

 47839                                  07 V((f))
214680                                  09 V
 36512                                  BO V
 37128                                  BO Ia
 41117                                  B2 Ia
206165                                  B2 Ib
120315                                  B3 V
 32630                                  B3 V
 53138                                  B3 Ia
 58350                                  B5 Ia
 34085                                  B8 Ia GRAYSTD/Wb
103287                                  A0 Van GRAYSTD
172167                                  A0 Va GRAYSTD
 87737                                  A0 Ib GRAYSTD
 21389                                  AO Ia
197345                                  A2 Ia
216956                                  A3 Va GRAYSTD
 89025                                  F0 IIIa
 36673                                  F0 Ib GRAYSTD
113139                                  F2 V
109358  GO V            GO V            GO V
121370                                  GO IV
204867  GO Ib           GO Ib
	G2 V            G2 V
 20630  G5 V            G5 V
161797  G5 IV           G5 IV           G5 IV
206859  G5 lb           G5 Ib
101501  G8 V            G8 V            G8 V
188512  G8 IV           G8 IV           G8 IV
 62345  G8 III          G8 IIIa         G8 III
113226  G8IIIab         G8 IIIab
 48329  G8 Ib           G8 Ib
185144  KO V            KO V            KO V
 62509                                  KO III
197989  KO III          KO- III         KO III
 22049  K2 V            K2 V
153210  K2 III          K2 III
127665                                  K3 III
201091  K5 V            K5 V            K5 V
164058  K5 III          K5 III          K5 III
  6860  MO+IIIa         MO+IIIa
  1013  M2+ III         M2+ III
 39801  M1-M2Ia-Iab var M1-M2 Ia-Iab
206936  M2- Ia          M2- Ia

  HD 161797:  G5 IV in atlas illustration, but IV-V in booklet table
  HD 222404:  K1 IV in atlas, but K1 IV CN1 in booklet table