P220/DIA/000 - Rectangular Diaphragm
This enables the experimenter to accurately define an area of interest within a field of view. It's twin levers provide independent adjustment in X and Y planes, allowing definition of a rectangle of arbitrary size and proportions. The dedicated holder C180 allows movement and rotation of the aperture defined by the diaphragm.
Used in conjunction with our infra-red viewing system; the area of interest can be viewed whilst photometric measurements are being made.
