I perusing the Peter Stetson 'homogeneous photometry' files, I noticed that he has reduced Arlo Landolt's data for the SU Tau field. This includes several nights in 2009 Sep, Nov, Dec and additional data from 2012 Jan, all using the Kitt Peak 2.1-m telescope. Stetson has supplemented this with a night from 1994 Sep by Frank Grundahl and others at La Palma (Stetson's log file says 'WHT 2.4m' telescope, presumably the William Herschel 4.2-m telescope, though the nearby Isaac Newton telescope is 2.4-m. Probably no matter.). About 11 nights are involved in total. For my own purposes I have abstracted the brightest stars from the Stetson list, which goes quite faint (SU Tau was in a deep minimum at the time of Landolt's work). Brighter stars in the field, which can extend the value of the sequence considerably, will have to be calibrated relative to these. I have a couple of nights as a start on this using the Lowell 1.1-m telescope.
I have matched the list against Arne Henden's similar two-night B,V dataset. On average the Henden values are fainter by 0.017 mag in V, and redder by 0.012 in B-V. These data, alas, do not include any of the brighter (mag 9-12) stars. A similar external comparison indicates APASS DR9 in this area is about 0.04 mag fainter than Stetson in V, but about right in B-V (large formal uncertainties). ASAS-3 V is pretty close to Stetson's zero-point.
The Stetson sequence covers the color ranges 0.26 < B-V < 2.08, and 0.07 < U-B < 2.16, and thus spans quite a wide range. The very red star SU_Tau-S66 is not variable in ASAS-SN. Because there are only eight stars involved, however, some additional fields would be good to get to fill gaps in the color range --- the nearby GD 71 Landolt field is very convenient for this.
The list below shows the basic data. The second line of each entry (if this comes across correctly) gives the mean errors per Stetson as a comma-delimited string, with those for the color-indices taken in quadrature from Stetson's separate magnitudes. The data involving B,V,I filters have high weight, but values involving U and R are relatively weak (i.e. U-B, V-R, R-I).
Presumably Stetson included SU Tau itself in the reductions, so 190-some high-quality data-points from Arlo should be available from those two years.
\Brian
source: https://www.canfar.net/storage/vault/list/STETSON/homogeneous/Latest_photometry_for_targets_with_at_least_BVI/SU_Tau_(UBVRI)
(2021 Aug 12 reductions)
Name RA (J2000) Dec V B-V U-B V-R R-I V-I
SU_Tau-S9 5 48 48.86 +19 06 10.1 12.218 0.255 0.260 0.145 0.153 0.298
0.0007,0.0067,0.0103,0.0087,0.0099,0.0049
SU_Tau-S16 5 48 54.19 +19 02 07.1 12.617 0.457 0.228 0.292 0.278 0.570
0.0009,0.0071,0.0071,0.0093,0.0103,0.0045
SU_Tau-S18 5 48 55.00 +19 05 05.0 13.611 1.309 0.692 0.783 0.761 1.544
0.0006,0.0065,0.0097,0.0102,0.0112,0.0045
SU_Tau-S20 5 48 56.48 +19 00 09.9 14.571 1.526 1.168 0.871 0.837 1.708
0.0007,0.0081,0.0115,0.0074,0.0087,0.0046
SU_Tau-S66 5 49 08.79 +19 06 18.0 14.071 2.081 2.160 1.242 1.135 2.377
0.0012,0.0106,0.0152,0.0092,0.0111,0.0065
SU_Tau-S40 5 49 11.36 +19 00 40.3 14.266 0.612 0.102 0.378 0.390 0.768
0.0006,0.0062,0.0094,0.0051,0.0069,0.0046
SU_Tau-S45 5 49 15.49 +18 59 52.3 13.762 0.516 0.068 0.318 0.338 0.656
0.0007,0.0064,0.0096,0.0068,0.0082,0.0046
SU_Tau-S50 5 49 17.58 +19 08 00.0 13.107 0.893 0.596 0.502 0.450 0.962
0.0006,0.0063,0.0096,0.0089,0.0100,0.0045