Best Spectrophotometric Standards

Best spectrophotometric standards:
                                      epoch  mu a cosd  mu d  Class   V Mag

LTT377         00 41 02.9  -33 44 06  1985                    f       11.2
Feige 24       02 32 30.9  +03 30 51  1950   +0.083   +0.010  DAwke   12.42
EG21           03 10 22.1  -68 39 28  1985                    DA      11.4 
G191B2B=EG247  05 01 31.5  +52 45 52  1950   +0.10    -0.0873 DAwk    11.78
GD71           05 49 34.79 +15 52 37  1950   +        -0.1898 DA1     13.03
LTT2415        05 56 24.2  -27 51 26  1985                            12.2
EG54           07 40 19.52 -17 24 41  2000  +1.136"/y -0.52"  DF      12.98 
LTT3218        08 41 33.6  -32 56 55  1985                    DA      11.8
EG63           08 47 29.6  -18 59 50  2000  -0.12"/y -0.05"/y DB      15.55
LTT3864        10 31 33.1  -35 33 03  1985                    f       12.1
Feige 34=EG71  10 36 41.1  +43 21 50  1950                    sdO     11.24
GD153          12 54 35.21 +22 18 09  1950            -0.1898 DA1     13.35
HZ 43 =EG98    13 14 00.7  +29 21 49  1950   -0.149   -0.0813 DAwk    12.91
HZ 44          13 21 19.1  +36 23 38  1950   -0.062   +0.031  sdO     11.67
EG274          16 23 33.7  -39 13 48  2000                    DA      11.0
LTT7379        18 36 26.2  -44 18 37  1985                    G0      10.2
HD 192281      20 10 46.8  +40 07 01  1950                    O5f      7.54
BD+284211=J256 21 48 57.1  +28 37 48  1950                    sdOp    10.56
LTT9239        22 52 40.88 -20 35 26  2000                    f       12.0
Feige110=EG158 23 17 23.5  -05 26 22  1950   +0.003   -0.003  sdO     11.88

OK standards:

Feige 25       02 36 00.0  +05 15 16  1950                    B6V     12.01
Hiltner 600    06 42 37.2  +02 11 25  1950                    B1V     10.42
Feige 56       12 04 13.8  +11 56 55  1950                    B5p     11.11
Feige 92       14 09 41.3  +50 21 07  1950                    Bp      11.62
BD+33 2642     15 50 02.9  +33 05 49  1950                    B2 IVp  10.88
BD+40 4032     20 06 40.0  +41 06 15  1950                    B2 III  10.45

The first set contains O stars without much Balmer absorption plus
faint southern standards from the list of Stone & Baldwin 1983, MN 204, 347.
The second set is mostly B stars that have a bit of Balmer absorption
and are usually OK.

from Link: https://www.cfa.harvard.edu/~dfabricant/huchra/standards.specp