Building a Stereoscope

Written by Dustin Martin

Dichoptic viewing apparatus with chinrest

     An apparatus for dichoptic viewing (i.e. stereoscope) is necessary for certain experiments (e.g. binocular rivalry) that require presenting separate images to each eye independently. Our stereoscope uses pairs of mirrors to reflect separate images to each eye. This guide provides assembly instructions for a stereoscope with HeadSpot and OptoSigma components.


     Many of the components of the dichoptic viewing apparatus are duplicates, used for each of the four mirror elements. The individual parts are labeled only with their respective part numbers. For this guide, the components will be referred to as follows:

  1. Optical Rail: 146-0390
  2. Optical Carriers: 146-1335
  3. Mirror Holders: 112-0256
  4. Round Mirrors: 033-0290
  5. Mirror Mounts: 112-0255
  6. HeadSpot chin rest
  7. AccessoRack


     The steps for assembly each of the four mirror elements are identical; however, it is necessary to assemble them so that each of the four mirrors faces a specific direction. The result should be two pairs of mirror elements that face each other (as pictured).

Dichoptic viewing mirror apparatus

1.  Insert a mirror into the mirror holder, with the arrow on the side of the mirror pointing out (below). If necessary, loosen the setscrew at the top of the mirror holder before inserting the mirror, and tighten down afterward.

Mirror inserted into frame, with arrow pointing out

2.  Loosen the setscrew at the top of the mirror mount using a hex key (below, left). Insert the mirror holder into the mirror mount and tighten the setscrew. Be careful not to overtighten, as this may damage the spring inside the mirror mount.


Loosen setscrew in mirror holderTighten setscrew in mirror holder








3.  Attach the mirror mount to the optical carrier using the thumbscrew included with the mirror mount.

Completed mirror element

4.  Rotate the mirror mount so that the mirrors in each pair are facing toward each other. The mirror should point outward from the optical carrier at a 45º angle.

Mirrors should point outward at a 45 degree angle

5.  Attach the completed mirror element to the optical rail such that the clamps on the optical carrier fit into the groove along the side of the rail. Tighten the thumbscrews to lock the mirror elements in place.

Mirror elements clamp into groove along side of barMirror elements fitted into groove in bar







6.  Repeat these steps for each of the four required mirror elements, arranging them so that they form two pairs, with the mirrors of each pair facing one another.

Mirror elements arranged on bar

7.  Attach the completed assembly to AccessoRack using the included bolts. Attach AccessoRack to the HeadSpot chin rest (see photo at the top of the page).

Bolts attaching bar to holderBolts attach bar to holder