Nikon DIAPHOT 300 - Page 33

3) Cover glass thickness
Each objective has an impressed mark of specified cover glass thickness. (A
mark “1 60/0.1 7" means an eyepiece tube length of 1 60mm and a specified
cover glass thickness of 0.1 7mm.)
For an objective with a 0.1 7 mark, place a specimen so that its cover glass
(0.1 7mm thick) faces the objective. (For an inverted microscope, set a
specimen so that its cover glass faces down.) For an objective with a 1 .2 mark,
place a specimen so that its slide glass faces the objective, because the normal
slide glass thickness is 1 ,2mm. (For an inverted microscope, set a specimen so
that its cover glass faces up.)
When you observe a specimen in a laboratory dish or the like at high
magnification through a glass not conforming to the specified thickness, we
recommend use of an objective that has a correction ring capable of correcting
the glass thickness error.
4) Oil immersion objective
The objective marked with ''Oil" is an oil immersion objective.
Before using the oil immersion objective, be sure to immerse the space between
the end of the objective and the specimen, in the optional oil (Nikon immersion
oil). When you carry out fluorescent microscopy using the oil immersion
objective for fluorescent microscopy, use the non-fluorescent oil (option).
Use care to keep out air bubbles from the oil, since they will deteriorate visibility
of images. Air bubbles may be found by observing the exit pupil (bright circle) of
the objective. (If the eyepiece tube BT1 is used, the exit pupil of the objective
can be observed by setting the turret assembly to B, bringing the Bertrand lens
into the optical path, and adjusting the focus with the Bertrand lens focusing
screw. If the eyepiece tube BT2 is used, the exit pupil can be observed by
removing the eyepiece, inserting the centering telescope, and rotating the
eyepiece into focus with the knurled ring held fixed.)
To remove air bubbles, rotate the revolving nosepiece slightly, and move the
oil-immersed objective back and forth once or twice. Or, wipe the oil off, then
reapply oil to the objective.
If excessive oil is applied, surplus oil flows out and adheres to the stage or other
component. Use a minimum necessary amount of oil (enough to fill the space
between the end of the objective and the specimen). Use care not to put oil to
any other components.
If oil remains on the oil immersion objective or adheres to the surface of a dry
objective, it will greatly reduce image visibility. After use, thoroughly wipe the oil
off the objective surface. Also make sure that no oil has spread to the surfaces of
other objectives.
To remove oil, moisten a lens tissue or clean cloth with xylene and lightly wipe
the lens surface a few times. For better results, use a fresh part of a lens tissue.