IMPORTANT MICROSCOPY TERMS
USING YOUR SILVERLINE MICROSCOPE
NUMERICAL APERTURE (NA)
A measure of an objective’s light gathering capabilities. The concept may be compared to the
F-valve in photographic lenses. Generally speaking, N.A. values of less than 1.00 are "Dry"
objectives. Values of 1.00 or greater require oil as a medium. Please note that condensers
are part of the optical system and are also assigned an N.A. value. That value must be at
least as high as that of the highest objective used
PARFOCAL
A term applied to objectives and eyepieces when practically no change in focus is needed
when changing objectives. The objectives on your SILVER3H microscope are parfocalled at
the factory so that only a slight adjustment of the fine focus knob is needed to maintain focus
when switching magnification.
RESOLUTION OR RESOLVING POWER
The ability of a lens to define the details of the specimen at a maximum magnification. This
is governed by the N.A. (Numerical Aperture) of the lens. For example, a 40X objective with
a N.A. of 0.65 has a maximum resolving power of 650X, equal to 1000 times the N.A.. This
rule of N.A. x 1000 is true of all achromatic objectives.
WORKING DISTANCE
The distance from the lens of the objective to the cover slip on the slide, when the specimen
is in focus.
CORDLESS OPERATION
The rechargeable battery should be fully charged for approximately 8 hours before the initial
use. It can be charged by using the 4.5 Volt A/C adapter included with the microscope. An
LED indicator light on the A/C adapter will be red while the battery is charging and will turn
green when the battery is fully charged.
The battery can be used to power the illumination system for approximately 40 hours. If the
microscope is used in the same location, the A/C adapter can remain plugged-in without
damage to the battery or recharging system.
SILVER
3H
SERIES
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SILVER
LINE
