Zeiss Standard 25 ICS Operating Manual

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Zeiss Standard 25 ICS Operating Manual Manual pdf 34 page image

Standard 25 ICS3-6 B 40-029 e 01/983.3 Setting of transmitted-light phase contrastThe phase contrast technique is mainly used to increase the image contrast of unstained specimens.As described in chapter 2, the microscope is ready for operation and switched on according to section3.1.The microscope must be set for transmitted-light brightfield, as described in section 3.2.The further steps depend on whether phase contrast equipment A or B is used.Optimum phase contrast requires a high level of cleanliness! Therefore, clean the front lens ofthe objective used, the visible condenser surfaces, the upper cover slip surface and the lowercarrier plate surface of the specimen with particular care and carefully remove grease.Equipment A condenser 0.9 Z (3-6/9) and Ph 2 phase stopcarrier (3-6/7) phase contrast objectives labelled "Ph 2"(3-6/11), suitable also for transmitted-lightbrightfieldSettings: Place unstained specimen on the mechanicalstage: Screw phase-contrast objective, e.g. 40x/0.65 Ph2 (3-6/11), into nosepiece and swing it into thebeam path. Remove condenser front lens 0.9 from the beampath via lever (3-6/10). Open the luminous-field diaphragm (3-6/5) andthe condenser aperture diaphragm (3-6/8). Swing in phase stop carrier (3-6/7) with Ph 2phase stop. Set the required brightness. Check whether phase stop centering complieswith figure (3-7/B). For this, remove oneeyepiece and replace it with the diopter or acentering telescope (3-6/3). If required, center the phase stop via the twocentering screws (3-6/6) using the SW 1.5screwdriver. The diopter or the centeringtelescope (3-6/3) must then be replaced with theeyepiece again.Fig. 3-6 Setting of phase contrast usingcondenser 0.9 Z