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The 290 variable wedge is an important tool for calibration of optical instruments.  Mounted in a stand-alone fixture made of cast bronze, the integrated glass block is rotated by a geared mechanism to produce an angular deviation in any line of sight which is roughly normal to the glass.  The "zero point" on the graduated scale may be rotated to either a horizontal or vertical position (index marks may be seen in the picture at the 12 o'clock and 3 o'clock positions), allowing either horizontal or vertical measurements to be made without physically relocating the entire unit.

The 290 is equipped with a control cable that is approximately 30" (76 cm) long for operator convenience in rotating the glass.  The cable is easily inserted and removed from the main unit.  For a replacement control cable, order part number 6454-G1.

The bottom of the unit has two tapped holes to aid in mounting (see specifications below for more information).

You may wish to see our other optical wedge, the model 390, on this website.