2. To zero the angle on the Rotary Motion Sensor:
a. With the D lens removed, rotate the spectrophotometer arm so the laser beam is centered on the Light Sensor slit. The spectrophotometer disk should be near 180 degrees but it doesn’t matter if it is slightly off.
b. Click on START and move the arm back and forth in front of the laser, watching the intensity in the digits display on the computer. Stop at the position that gives the maximum intensity. Click on STOP and do not move the arm until program is started to take the actual data run. This insures that zero for Rotary Motion Sensor is at the center of the beam.
c. Place D lens on the platform against the step, centering it.