Zeiss Axiolab A Operating Manual

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Zeiss Axiolab A Operating Manual Manual pdf 28 page image

Carl Zeiss Axiolab A1-18 06/99 B 40-015 e1.5 ObjectivesThe objectives are the optical centerpiece of the microscope. The following is an example of howobjectives can be labelled:Epiplan 10×/0.20 ∞/-where10× : objective magnification, with a defined color ring on the objective being allocated to eachmagnification step (Carl Zeiss color ring code)0.20 : numerical aperture∞ : infinite tube length- : can be used with cover slip thickness D = 0 or 0.17 mmor0 : can only be used without cover slip, that means D = 00.17 : can be used with cover slip thickness D = 0.17 mmandOil : oil immersion objectivePh 2 : phase contrast objective with a green color ring and phase stop Ph 2Color ring code for objective magnificationColor ring onobjectiveblack brown red orange yellow green lightbluedarkbluewhiteMagnificationfactor1.25× 2.5× 4×; 5× 6.3× 10× 16×;20×;25×;32×40×; 50× 63× 100×;150×The objective magnification multiplied with the eyepiece magnification (usually 10×) results in the visualoverall magnification: e.g. 10 × 10 = 100×.The numerical aperture × 1000, e.g. 0.20 × 1000 = 200×, is the highest useful magnification, i.e. nofurther details are resolved above that limit.In transmitted-light applications, the exact observance of the cover slip thickness of 0.17 mm is all themore necessary the higher the numeric aperture of the objective. Therefore, so-called "Korr" objectivescan be set for different cover slip thicknesses via a correction ring. For this, a specimen area is searched,and the position of the correction ring where optimum focus and image contrast are obtained isdetermined (refocusing is always required).Immersion objectives are always insensitive to differences in cover slip thickness.When immersion objectives are used, the air between the cover slip and the objective is replaced with aliquid, which is immersion oil in most cases. The plastic oiler containing 20 ml of 581 N immersion oil isparticularly suitable for this purpose.