Swift STELLAR 1 Series Instruction Manual page 3

Microscope terminology
Abbe Condenser
A two-lens sub-stage condenser
located below the stage of a
microscope and functions to
collect light and direct it onto
the object being examined. Its
high numerical aperture makes
it particularly suited for use
with most medium- and high-
magnification objectives.
Aperture, Numerical (N.A.)
The numerical aperture is an
important factor determining the
efficiency of the condenser and
objective. It is represented by the
formula: (N.A. = ηsinα), where
η is the refractive index of a
medium (air, water, immersion oil
etc.) between the objective and
the specimen or condenser, and
α is half of the maximum angle
at which light enters or leaves
the lens from or to a focused
object point on the optical axis.
Cover Glass Thickness
Transmitted light objectives are
designed to image specimens
that are covered by a thin cover
glass (cover slip). The thickness
of this small glass piece is now
standardized at 0.17 mm for
most applications.
Diaphragm, Condenser
A diaphragm, which controls the
effective size of the condenser
aperture. A synonym for the
condenser illuminating aperture
diaphragm.
Magnification
The number of times by which the
size of the image exceeds the original
object. Lateral magnification is usually
meant. It is the ratio of the distance
between two points in the image
to the distance between the two
corresponding points in the object.
Micrometer (um)
A metric unit of length measurement
-6
= 1x10 meters or 0.000001 meters
Nanometer (nm)
A unit of length in the metric system
-9
equal to 10 meters.
Phase–contrast (microscopy)
A form of microscopy, which converts
differences in object thickness and
refractive index into differences in
image amplitude and intensity.
Real Viewfield
The diameter in millimetres of the
object field.
Eyepiece Field of View
Real Viewfield =
For example Stellar 1:
Eyepiece field of view
Objective magnification
Diameter of the object field = 18/10
2
Objective Magnification
= 10mm
= 10X
= 1.8mm