Reads to 6 minutes of arc (0.1°) 170 mm diameter metal scale graduated 360° x 1°, independently rotatable, with locking screw, vernier attached to the telescope reads to 0.1° (6 minutes of arc). Collimator is mounted on a fixed pillar, with an achromatic objective of 150 mm focal length and 21 mm aperture, and has an adjustable slit 6 mm long. The telescope is on a movable pillar, with a fine adjustment screw, an achromatic objective of 170 mm focal length, 21 mm aperture, Ramsden eye-piece and glass crosswire graticule. Both collimator and telescope have spiral focusing system and have axis adjusting arrangement. The table has 3 leveling screws, with lines marked to assist prism placement. With prism and grating holders, one small screwdriver and one Tommy bar for axis adjustment. Without prism.