First HST/FOC images of the low mass companion of the astrometric binary Gliese 623.

We have resolved the astrometric binary Gliese 623 into two components, by direct imaging in the visible band, with the COSTAR corrected FOC. The images clearly show the faint companion Gliese 623B, with a derived absolute magnitude of M_V_=16.17+/-0.10, at a distance of 0.33" from the primary (namely at 2.51AU, assuming a parallax of π=0.132", i.e. a distance of 7.6pc). From the mass-luminosity relationship of Henry and McCarthy (1993AJ....106..773H), the photometric mass of the secondary is 0.098 solar masses.