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OPERATION
ZEISS
Using objectives
Axio Observer
98
431004-7244-001
12/2016
Using LD objectives
When working with inverted microscopes, vessels
are common whose bottom thickness deviates
significantly from the usual cover slip thickness of
0.17 mm.
Normally, working distances (a) of objectives with
low magnification can bridge these distances
without any problem:
−
A-Plan 5x / 0.12 a= 10.9 mm (in air)
or
−
A-Plan 10x / 0.25 a= 5.3 mm (in air)
However, in the mid-range magnification area
these working distances shrink usually to values
around or below 1 mm. Such objectives cannot be
used for thicker vessel bottoms.
To remedy this deficiency, special LD objectives (Long Distance) can be used. They have a relatively large
working distance and at the same time the usual parfocal distance of 45 mm of all other objectives.
Insert the corresponding Coverglass cap 422904-9000-000 (Fig. 81/
1
) onto the objective to adapt LD A-
Plan objectives to thin bottoms or cover slips.
Using corr objectives
The exact thickness of the cover slip is important for an excellent image.
For this reason, corr objectives can be adjusted for different cover slip thicknesses using a correction
collar.
To do this, select an area of the specimen, and find the correction collar position which produces the
optimum focus and image contrast (refocusing will always be necessary).
ATTENTION
The specimen plane must be no more than 2.5 mm above the stage plane to prevent the
LD corr objective hitting the underside of the stage.
Specimen with a vessel bottom of 1 mm can be focussed if the vessel is moved using the object
guide and mounting frame. Under this condition all objectives can be swiveled through the
travel range on the specimen stage without collisions.
Fig. 81
Working with LD objectives
Summary of Contents for Axio Observer Series
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