Accurate rocket observations are needed to estimate the post-launch sensitivity of the Wisconsin OAO instruments and to set the absolute scale of the OAO broad-band photometry and spectrophotometry. Seven broad-band photometers, equipping a pointable Aerobee rocket, are calibrated against a source of synchrotron radiation in an attempt to determine, as accurately as possible, the absolute energy distribution of OAO reference stars. The first flight (July 1st, 1970) failed for technical reasons but the experiment will be repeated in 1971.