Abstract
Until recently the recording of fully corrected excitation and fluorescence spectra from fluorophores in microscopic preparations has been a time-consuming procedure. A new type of microspectrofluorometer with epi-illumination has been developed. This instrument is operated on line with a digital computer permitting automatic operation of monochromator motors, electrical shutters and correction of spectra. The electrical shutters are used for a rapid change between low intensity dia- and strong epi-illumination. Exposure to epi-illumination is limited to the short period of recording the spectra. A new optical system permits centering of structures to be measured, using the binocular head for viewing the illuminated image of the monochromator slit and the fluorescent image excited with dia-illumination simultaneously. New objectives and eyepieces with a high light collecting power permit the visualization of weak fluorescence obtained with low intensity dia-illumination.