Hipparcos red stars in the HpV_T2 and $V\!I_{\rm C}$ systems

For Hipparcos M, S, and C spectral type stars, we provide calibrated instantaneous (epoch) Cousins $V\!-\!I$ color indices using newly derived HpV T2 photometry. Three new sets of ground-based Cousins $V\!I$ data have been obtained for more than 170 carbon and red M giants. These datasets in combination with the published sources of $V\!I$ photometry served to obtain the calibration curves linking Hipparcos/Tycho $Hp-V_{\rm T2}$ with the Cousins $V\!-\!I$ index. In total, 321 carbon stars and 4464 M- and S-type stars have new $V\!-\!I$ indices. The standard error of the mean $V\!-\!I$ is about 0.1 mag or better down to $Hp\approx9$ although it deteriorates rapidly at fainter magnitudes. These $V\!-\!I$ indices can be used to verify the published Hipparcos $V\!-\!I$ color indices. Thus, we have identified a handful of new cases where, instead of the real target, a random field star has been observed. A considerable fraction of the DMSA/C and DMSA/V solutions for red stars appear not to be warranted. Most likely such spurious solutions may originate from usage of a heavily biased color in the astrometric processing.