Turret Phase Contrast Condenser; Phase Annulus - Accu-Scope EXC-400 Manual

ADJUSTMENT & OPERATION
③
②
Fig. 28
④
⑤
Fig. 29
IMPORTANT: Proper phase annulus
halo centration is essential for quality
phase contrast observation.
If a double halo appears, center the
brightest halo to the objective phase
ring.
®
ACCU-SCOPE
③
①
73 Mall Drive, Commack, NY 11725 • 631-864-1000 • www.accu-scope.com
EXC-400 MICROSCOPE SERIES
(continued)
Assembling & Operating
Turret Phase Contrast Condenser– (Fig. 28)
The phase contrast condenser contains positions for
magnification-specific ring diaphragms and a brightfield "BF"
position on the condenser turret ①. In phase contrast
observation, the ring diaphragm magnification shown on the
condenser turret ① should match with the magnification of the
phase contrast objective.
For brightfield observation, turn the condenser turret ① to
"BF" position. Detents provide "click stops" when the
condenser turret ① has reached a position for observation (a
diaphragm or BF position is centered in the optical path (see
Fig. 28).
Centering the Phase Annulus – (Fig. 28 & 29)
(1) Rotate the 10X phase contrast objective into the light path,
then rotate the condenser turret ① to the 10X position.
(2) Turn the aperture diaphragm lever ② all the way to the left
(most open). Always keep the aperture diaphragm fully
open for phase contrast observation.
(3) Place a specimen on the stage and focus.
(4) Remove one observation eyepiece and place a centering
telescope (CT) into the empty eye tube. Ensure that the CT is
in the eye tube without a diopter adjustment.
(5) Loosen the lock screw of the centering telescope, slide the
telescope tube up and down until the image of the phase
annulus ④ (halo) and phase ring ⑤ are clear and in focus.
Lock the screw to hold the position. (See Fig. 28 & 29)
(6) If the phase annulus and phase ring are not centered
and perfectly overlaid, use the phase contrast ring adjusting
lever ③ to center the annulus (the phase ring ⑤ cannot
move). While observing through the centering telescope, press
the phase contrast ring adjusting levers into the condenser,
then twist each left or right to align and center the phase
annulus halo ④ over the phase ring ⑤. A properly aligned
and centered phase annulus halo ④ will appear as in the right
side of Fig. 29.
(7) Remove the CT from the eye tube, and reinsert the
eyepiece to observe the phase contrast effect.
(8) Adjust the other phase contrast annuli ④ for the other
phase contrast objective magnifications according to the steps
above.
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