Schematic representations of the concepts of (a) the RED method and (b) the ADT method. Both can be used to collect ED data by rotating a crystal around an axis in steps of 1–3° using goniometer rotation. To cover the gaps between goniometer rotations, RED uses a fine beam tilt (typically 0.05–0.2°), while ADT is often coupled with precession ED. (a) Reprinted (adapted) with permission from Wan et al. (2013). (b) Reprinted (adapted) with permission from Mugnaioli & Kolb (2013). Copyright (2013) Elsevier.