Takahashi E-160ED, Инструкция по эксплуатации

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Next, when you check the position of the 3.
secondary mirror mark again, it should be
above the intersection of the crosshairs
as shown in Fig. C-21. In this case,
loosen 1 and 4 in Fig. C-19 and tighten
the screws 2 and 3. The secondary mirror
mark approaches the intersection of the
crosshairs, so when you come to the
horizontal line, look up and down again
to check the widths, firmly squeeze the
spider pull screw, and set the lock nut
with a spanner. Perform adjustments as
necessary until it becomes as shown in
Fig. C-16.
Check the following:
Secondary mirror: the intersection of •
the crosshairs and the secondary mark
overlap, and that point is at the center of
the collimating eyepiece.
Primary mirror: the mark of the primary •
mirror is at the intersection on the
extension line of the spider blade.
The sides of the spider / secondary mirror •
outer cylinder have the same width when
viewed from above and below.
If these are confirmed, the adjustments are
complete.
Star image test
ی
Photo test ▼
After adjusting the optical axis with the
centering eyepiece, the in-focus and out-
of-focus airy disks are checked visually, but
since the ε-160ED is an astro camera, it is
better to evaluate a test image. That way,
you can detect a deviation of the optical axis
from the edge of the image.
For this test, select an image which has the
sharpest central image from the previewed
images. Enlarge the edge of the image to
check the quality of the stars.
The star image is elongated •
The star image is • bloated
If any of the issue above are present, it
Spider Lock Nut
Optical Axis Set Screw
Spider Pull Screw
Figure C-19
Figure C-20 Figure C-21
A
B
C
could be caused by the misalignment of the
optical axis. By repeating the image test
while recording the changes in edge of the
image, you will be able to obtain consistently
good results.
Visual test ▼
Since the diagonal mirror of the ε-160ED is
off-set to produce a fully illuminated image
circle, when the visual image is defocused
the diffraction ring will appear eccentric. This
is perfectly normal. This is not an indication
of decollimation.