Abstract: Disclosed is an optical device with at least one lens and at least one swiveling observation tube, exhibiting the following characteristics: The observation tube comprises a base section fixedly connected to the optical device, and an eyepiece carrier which rolls along an arc of a circle so that swiveling can occur on the base section; a first rotatable deflecting mirror whose rotational axis orthogonally intersects the optical axis of an objective lens of the optical device and which is forcibly rotated by the movement of the eyepiece carrier on the base section; a second rotatable deflecting mirror is arranged in the eyepiece carrier and whose rotational axis orthogonally intersects the optical axis as deflected by the first deflecting mirror and which is forcibly rotated by the movement of the eyepiece carrier on the base section.