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When telescope and vertical circle are rotating with horizontal axis on which plane?
Horizontal plane
Vertical plane
Inclined plane
Both A and B
Vertical plane
In a theodolite, the telescope and the vertical circle are rigidly fixed to the trunnion axis (horizontal axis) ┬╖ As the telescope rotates about this horizontal axis to measure vertical angles, the rotation occurs within a plane perpendicular to the trunnion axis, which is defined as the vertical plane.
In a theodolite, the telescope and the vertical circle are rigidly fixed to the trunnion axis (horizontal axis) ┬╖ As the telescope rotates about this horizontal axis to measure vertical angles, the rotation occurs within a plane perpendicular to the trunnion axis, which is defined as the vertical plane.
V=Dtan(╬▒) тАФ where V is vertical height, D is horizontal distance, and ╬▒ is the vertical angle measured via rotation in the vertical plane.
The horizontal axis (trunnion axis) serves as the axis of rotation for the telescope in the vertical plane ┬╖ By rotating the telescope around this fixed horizontal pivot, the line of sight moves along a vertical arc, allowing for the measurement of zenith or elevation angles relative to the gravity vector (or horizontal datum).
The horizontal axis is perpendicular to the vertical axis of the theodolite.
Rotation about the horizontal axis is essential for measuring vertical angles (elevation/depression).
The vertical circle is attached to the telescope and rotates with it.
The plane of the vertical circle remains parallel to the line of sight during rotation.
Allows precise measurement of elevation angles.
Facilitates leveling and slope distance correction.
Requires proper temporary adjustments (leveling) to ensure the vertical plane is truly vertical.
Sensitive to index error in the vertical circle.
Tacheometry
Trigonometric leveling
Setting out grades in construction
The horizontal axis is also known as the trunnion axis.
The vertical axis is the axis about which the theodolite rotates in the horizontal plane (azimuth measurement).
B is correct тАФ The telescope and vertical circle rotate about the horizontal axis within a vertical plane to measure vertical angles.
Always remember: Rotation about the Horizontal axis measures Vertical angles, while rotation about the Vertical axis measures Horizontal angles (Azimuth).