Abstract: This invention relates to a stereo microscope comprising light collection means for collecting two angularly separated beams of rays from an object, a light path for each beam to guide said beam from said light collection means to an eye-piece and magnification means associated with each light path, whereby on viewing simultaneously the beam leaving each light path, a magnified stereoscopic image of the object is obtained, characterized in that the light collection means for each path comprises a first reflecting surface, and a second reflecting surface in spaced relationship with a first reflecting surface, in which each first surface is adapted to receive and reflect a beam from an object to said second reflecting surface, the beams reflected from the second reflecting surface being disposed along substantially spaced parallel axes.

Abstract: A dual viewing optical system, for attachment to an optical instrument, hng beam splitting means which can provide first and second beams of light, a first viewing position at which the first beam can be viewed, attached to the beam splitting means a first tube along which the second beam can pass, the said first tube having a coaxial joint which allows coaxial relative rotation of the ends of the tube, a remote eye piece attached to the end of said tube remote from the beam splitting means by a first swivel joint which can rotate about an axis perpendicular to the axis of the tube and allow the axial length of the remote eye piece to be pivoted about said axis of the swivel joint in a plane parallel to but displaced from the axis of the said tube, whereby the remote eye piece may lie in any spatial direction relative to the direction of the first beam, and optical means to relay the second beam to the remote eye piece.