Vixen BT80M-A User manual

VIXEN BT80M-A BINOCULAR TELESCOPE
Eyepiece Eyepiece Lock Ring
Focusing Ring
Prism Housing
Diagonal Prism Housing
Photo Tripod Adapter
Objective Lens
Lens Shade
Body Tube Handle
Vixen BT80M-A Specifications:
Objective Performance
Aperture 80mm Magnification 36x
Focal Length 900mm Angular field of view 1.11
Aperture Ratio 1:11.2 Linear Field of View 19m at 1000m
Optical Composition 2 Air spaced compo-
nents with built in tele-
extender
Exit Pupil 2.22m
Magnification can be changed by using other op-
tional Vixen NLV Eyepieces
Coatings Magenta coated
Eyepiece Measurements
Optical Composition 2 group - 4 element
OR25mm
Size 23 in x 7.5 in x 8.5 in
(58cm x 19cm x 21.5cm)
Coatings Multi Coated Weight 11 lbs (5kg)
Using your BT80M-A Vixen Binocular Telescope
1. To install on a photo tripod, screw the photo tripod adapter on the pan head of the tripod.
2. Aligning 3 Dots: Align the three dots marked on the eyepiece, focusing ring and prism housing in
red for the right side of the binocular telescope and in green for the left side. Optical axis is now
collimated and focus is adjusted to infinity.
3. Adjust the inter pupillary distance: Hold the right and left prism housings with your hand and
look through the binocular telescope while turning them until one clear circle of image is seen.
4. Focusing: Close your left eye and look through the right eyepiece with your right eye. Rotate the
focusing ring of the right eyepiece until the image appears in sharp focus. Next, close your right
eye and look through the left eyepiece with your left eye. Rotate the focusing ring of the left
eyepiece until the image appears in sharp focus.

Vary the magnification by using other Vixen NLV Eyepieces. However, these are not marked
with aligning dots for collimating the optical axes. The following adjustment may be required.
Look through the left eyepiece and find an object in ex-
cess of 1000 yds away. Bring the object to the right edge
of the horizontal center in the field of view. Then look
through the right eyepiece. If the object is seen at a level
with the image of the left eyepiece, the optical collimation
is good. If not, rotate the right eyepiece slowly clockwise
or counter clockwise until it is seen at a level with the im-
age in the left eyepiece.
If it is not possible to level it with the image of the left
eyepiece by rotating the right eyepiece. Try to do the
same adjustment as the above by rotating the left eyepiece.
Note: At a low power, an object can be seen clearly and brightly. It is advisable to being
with a low power eyepiece having a long focal length and to change it gradually to a high
power eyepiece having a short focal length. When using the nlv25mm eyepiece on the Vixen
BT80M-A, power will by 36x which is fairly high in comparison with magnification of ordi-
nary binoculars.