Readings of angular displacement of 0.5 second of arc using an easy-to-read large-diameter micrometer drum.

The 6D employs a 70mm aperture lens to product clear, reflected images. It also features extremely accurate double line reticles for improved detection.

The 6D Autocollimator makes high-precision measurements simultaneously on two axes with the darkfield technique. It projects a bright crossline and Nikon's most popular model because the bright-line cross is the easiest to see.