Abstract
Without invoking anomalous dispersion and heavy-atom derivatives, we demonstrate the direct phase determination of a large number of reflections collected in a short time from macromolecular crystals using a stereoscopic oscillation-crystal imaging technique, in a multi-beam diffraction geometry, where two crystallographic axes in opposite directions are employed as the rotation axes. The intensity profiles (distributions) of the diffraction spots versus the varying tilt Bragg angle of the rotation axis in the stereoscopically-related two images yield quantitative phase information.This technique thus provides a new practical way for direct phase determination of macromolecular crystals.