Question

when upper clamp and upper tangent screw is used?​

Answer 1

When clamped, the instrument can be gradually transited around the circle by use of the upper horizontal tangent screw. It is the upper clamp and tangent screw which are used during a sequence or "round" of horizontal angle measurements. 8.

Answer 2

Explanation:-

When clamped, the instrument can be gradually transited around the circle by use of the upper horizontal tangent screw. It is the upper clamp and tangent screw which are used during a sequence or "round" of horizontal angle measurements.