VWR Visiscope 400 Serie Manual De Instrucciones página 12

Centering the ring
► Usually this operation is not needed. If
necessary, please proceed with the fol-
lowing steps:
1. Place a specimen on the stage and focus
it.
2. Take out the eyepiece from the tube with-
out the dioptric adjustment, and replace it
with the centering telescope (CT). (Fig.28)
3. Check that the phase ring and the objective
correspond, and that both are steadily set
on a click stop.
4. Use the CT to focus on the light ring's im-
age ① and the phase contrast ring's image
②. If the light ring's image is not sharp, ad-
just the CT's eyepiece until you can see a
clear image of the light ring.
5. Adjust the bolts of the two centering holes
in the phase contrast slider using a screw-
driver until the light ring center and the
phase contrast ring center coincide.
6. The 10X and the 20X phase contrast objec-
tives use the same ring on the phase con-
trast slider. The coincidence of the light ring
center and the phase contrast center must
be verified with both objectives.
(Fig.29; Fig.30)
► If the light ring is centered incorrectly,
the contrast will be severely impaired.
► The phase ring may need recentering
during and after observation of very
thick specimens.
► The phase ring may show an apparent
misalignment if the cover glass is not
flat.
②
12
①
Fig.28
Fig.29
Fig.30