Setting Up Parallel Illumination on the Talos Arctica for High-Resolution Data Collection.Illuminating a specimen with a parallel electron beam is critical for many experiments in transmission electron microscopy as deviations from this condition cause considerable deterioration of image quality.  It was recently shown that a Thermo Fisher Scientific Talos Arctica, a two-condenser lens TEM operating at 200 kV, equipped with a Gatan K2 Summit direct electron detector is capable of resolving frozen-hydrated macromolecules of various sizes and internal symmetries to better than 3 Å resolution using single particle methodologies.  Here, this chapter describes how to establish parallel illumination conditions in a Talos Arctica TEM for high-resolution cryogenic data collection for structure determination.
Talos Arctica
It was recently shown that a Thermo Fisher Scientific Talos Arctica, a two-condenser lens TEM operating at 200 kV, equipped with a Gatan K2 Summit direct electron detector is capable of resolving frozen-hydrated macromolecules of various sizes and internal symmetries to better than 3 Å resolution using single particle methodologies. 
Gatan K2 Summit direct electron detector