The original Wide Field and Planetary Camera (WF/PC-1) served as the prototype for WFPC2. In many respects the two instruments are very similar. ... The instrument was built at the Jet Propulsion Laboratory (JPL) and was launched aboard HST in April 1990. ... After the discovery of spherical aberration in the HST primary mirror, it was quickly realized that a modification of the WFPC2 internal optics could correct the aberration and restore most of the originally expected imaging performance. ...