Nothing can be done if the optical tube is not perpendicular to the declination axis or if the R.A. and Dec axes are not perpendicular, because these problems are next to impossible to fix.

• 但没有避光学镜筒没有垂直于赤纬轴，或是赤纬轴与赤经轴没有互相垂直更糟的情况，因为这需问题会导致根本无法固定住要观测的目标。