Axial tilt

As axis tilt (also tilt axis, Achsschiefe ), in a meter refers to the deviation of an axis of the horizontal or the vertical. In astronomy is called ( orbit ) as axial inclination, the angle between the axis of rotation of a celestial body and its orbital plane.

Measurement

An axial inclination affects a i as a systematic error on the measurement and must therefore be considered separately and are elininiert. It is most common method to attach an accurate spirit level or a digital sensor to the axis, and then read during the measurement, as well as in the opposite orientation of the device.

In universal instruments and theodolites following Achsneigungen be distinguished:

• Vertical axis error - the deviation of the vertical axis of rotation from the perpendicular direction. It is desirable to keep him already setting up the instrument at about 10 " and measure the rest by the Alhidaden or tab dragonfly or a sensory compensator. Its effect on a target point increases with the tangent of the angle of elevation to.
• Tilt Axis - the inclination of the horizontal axis on which the riflescope sits; but also the structurally related non- orthogonality between standing and tilting axis. They can be eliminated by measurement in two circuit layers.
• Collimation axis error - the non- orthogonality between tilt and target axis. It can also be eliminated by the measurement arrangement, but must first be brought about by adjustment of the reticle to a value below about 10 "( which corresponds to about 0.01 mm).

When leveling only the axial inclination in the direction of the telescope is relevant and is automatically compensated by a precise pendulum bob with modern instruments ( Automatic Level ). In channel lasers and other objective instruments they must be brought to zero by accurate calibration while it is in fixed equipment mechanical engineering eliminated by adjustment in the camps.

Astronomy

The axial inclination of a planet or moon is the angle between its axis of rotation and normal to the plane of its orbit. It determines, inter alia, the seasons appearing on this celestial body. The Earth currently has an axial inclination of 23 ° 27 ', which also defines the polar circles and the tropics.

Achsneigungen between 90 ° and 270 ° indicate a retrograde ( downward ) rotation.