Hubble Space Telescope observations of the gravitational lens system B1422+231

Hubble Space Telescope observations of the gravitational lens system B1422+231 are presented. The spectra of the four components are virtually identical, although there are differences among the Ly alpha emission-line equivalent widths that might be due to microlensing. There are also significant differences between the component flux density ratios measured at radio and optical wavelengths. High-resolution imaging reveals the lens close to the faintest quasar image. The lens has photometric properties consistent with an elliptical galaxy at z similar to 0.4. The addition of new constraints to simple lensing models affirms the B1422+231 system as a suitable tool for an eventual direct measure of the Hubble constant.