The Earth's axis is positioned at an angle of 23.5 degrees away from the plane of the ecliptic. An objects axis, or axial tilt, also referred to as obliquity, is the angle between an objects orbital axis and rotational axis, or regularly, the angle between its orbital plane and equatorial plane.
The Earth's axis is determined through a number of steps. The first is to locate the line which passes through the sun's north and south equators. The next step is to use the plane of the ecliptic, which is an imaginary disc that surrounds the suns equator in all directions and that is also where all of the planets in the solar system are located. The Earth's axis is determined by measuring its angle in relation to the sun's axis of rotation.