Figure 12.17.2.

Schematics of optical apparatus with direct illumination. An alternative design for dual optical mapping was used for large fields of view where the light beam from tungsten-halogen lamps can be directly focused on the heart and fluorescence images from the heart are split with a dichroic element and refocused on the surface of two Hamamatsu PDAs. The dichroic element can be rotated and replaced with a mirror to focus an image of the heart on a graticule placed on a parafocal plane and with the exact dimensions of the surface of the PDA. The image of the heart that is focused on the graticule will be automatically focused on the surfaces of the two PDAs.