III. Operation of each part
46
Cover glass thickness
On every objective, there is a mark indicating the thickness of the cover glass to be used with. (“
∞
/ 0.17” means to use
a cover glass of 0.17 mm thick.) When observing with a “0.17” marked objective, place a specimen so that its cover glass
(0.17 mm thick) faces the objective. (In case of 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 1.2 mm. (In case of 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.
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,
with the supplied oil (Nikon immersion oil). Use the non-fluorescent oil (option) when you carry out fluorescent
microscopy using the oil immersion objective for fluorescent microscopy.
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. (To observe the exit pupil of the objective, turn the eyepiece tube turret to
position “B” and focus with the Bertrand lens focusing screw. If your microscope does not have an eyepiece tube turret,
remove one eyepiece and insert the centering telescope with an adapter and turn the eyepiece part of the centering
telescope to focus.)
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 petroleum benzine and lightly wipe the lens surface a few times.
Use a fresh part of a lens tissue every time. For best results, wipe last with absolute alcohol (ethyl or methyl alcohol).
If you cannot obtain petroleum benzine, use methyl alcohol. Because methyl alcohol is a weaker cleaning agent, you will
need to wipe the surface repeatedly. (Usually, three or four wipes are adequate to clean the surface.)
Absolute alcohol and petroleum benzine are quite inflammable. Use great care when handling them and when setting the
power switch on and off. Be very careful with fire.
The use of acrylic stage ring (option) will facilitate the immersion operation with the culture dish left on the stage. Set the
stage ring so that its opening runs along the rim of the revolving nosepiece. Rotate the nosepiece till the objective shows
from the opening of the stage ring and hold the nosepiece there to immerse the top lens of the objective.
Water immersion objective
The objective marked with “WI” is a water immersion objective. (The one with longer working distance is for the upright
type microscopes.)
Before using the water immersion objective, be sure to immerse the space between the end of the objective and the
specimen, with the demineralized or distilled water. (Do not use the tap water for immersion since when it dries up,
impurities will stuck on the lens surface and may cause a scratch during cleaning.)
Plan Apo 60xWI objective (N.A. = 1.2) has a correction ring to compensate the difference of the cover glass thickness for
the best abberation compensation. The mark “17” on the graduation shows the position for the 0.17 mm thick cover glass.
Before using the cover glass, measure its thickness with the micrometer or the like, and set the correction ring to match
that thickness for the best compensation.
