The limitation of spatial resolution in orientation imaging via electron backscattered diffraction analysis in the scanning electron microscope (SEM) makes it difficult to investigate the microstructure of nanocrystalline materials. The use of the recently developed transmission electron microscope (TEM) based product, known as ASTAR, offers the possibility of reliable orientation/phase mapping with a spatial resolution below 3 nm. In ASTAR, a nanoprobe electron beam is scanned over the specimen, and spot diffraction patterns are collected. The electron beam is precessed to reduce dynamical effects and improve pattern quality. Using template matching, the diffraction patterns are indexed automatically.