Abstract: A heavy-duty precision support for an optical instrument, especially for an astronomical telescope is disclosed, comprising a base carrier which is mounted on a stationary base so as to be rotatable about a vertical axis and an instrument holder for holding the optical instrument which is supported at the base carrier so as to be swivelable about a horizontal axis. To provide a support which is simple to produce and assemble and which has excellent stiffness, positioning accuracy and dependability, the base carrier is supported against the base in the manner of a ball joint by means of a central bearing. Further, a bearing portion of the base carrier is guided axially at the base.