Orion BT70 - Manual (Page 2)

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The BT70 is a true binocular telescope, with optical quality
and features you’d expect of a fine astronomical instrument.
The included eyepieces provide 20x magnification, but
optional interchangeable eyepieces (available from Orion)
let you vary the magnification for deep-sky, solar system,
and terrestrial viewing - with 3D-like depth of field! The 90°
eyepiece viewing angle makes nighttime observing more
comfortable, as the binoculars don’t need to be positioned
above your head when looking upwards. The rugged body
construction and waterproof design ensure the BT70’s will
provide viewing enjoyment for years to come.
Please take the time to read this instruction sheet before
using your new binoculars.
using a tripod
When observing with large-aperture binoculars like the
Orion BT70s, a sturdy photo tripod or altazimuth mount is
required. This is because the weight and magnification of
the binoculars make it impossible to hold them steady with
your hands.
To attach the BT70 to a photo tripod, simply thread the
tripod’s 1⁄4"-20 mounting stud into the threaded hole in the
BT70’s mounting plate. The tripod must be able to support
approximately 10 lbs., otherwise it may not be stable
enough for the BT70.
To attach the BT70 to an altazimuth mount that utilizes a
dovetail holder, like the Orion VersaGo mount, an optional
dovetail L-bracket is needed. The L-bracket connects to the
BT70’s mounting plate, and has a dovetail bar that goes
directly into the mount’s dovetail holder. Contact Orion to
order this optional L-bracket.
inserting the Eyepieces
Perhaps the most unique feature of the BT70 is its ability
to change eyepieces. The two supplied eyepieces provide
a magnification of 20x, but other magnifications can be
obtained by purchasing optional eyepiece sets from Orion.
To install the eyepieces, first remove the cover caps from
the binoculars and eyepieces. Then, simply insert the
eyepieces into the binoculars’ eyepiece holders (Figure
1). Push the eyepieces into the holders until they are fully
seated. To remove the eyepieces, just pull the eyepieces
out of their holders.
Extending the lens Shades
Another nice feature of the BT70 is its extendable lens
shades (Figure 1). These increase image contrast by
preventing glare (unwanted stray light) from entering the
objective lenses of the binoculars. They also slow the
formation of dew on the objective lens exteriors. To use the
lens shades, grasp them with your fingers, and pull them
outwards.
You will need to retract the lens shades to fit the binoculars
into its case.
adjusting the Distance Between Your Eyes
(interpupillary Distance)
Adjusting the interpupillary (IP) distance of the BT70 is
incredibly easy. Simply turn the chrome IP knob located
between the eyepieces. Rotate the knob until the distance
between the eyepieces matches the distance between your
eyes. When properly adjusted, you should see a single,
round field of view when looking through the binoculars.
Make this adjustment before you attempt to focus the
binoculars.
Focusing
The BT70 binoculars utilize individual focus eyepieces.
This makes the binoculars mechanically more rugged than
similar center-focus models, and generally maintains optical
alignment better. For astronomical observation, individual
focus eyepieces are usually preferred.
Pick an object in the distance to view. At night, best focus
will be achieved by focusing on a bright star. Cover your
right eye (or cover the right objective lens of the binocular)
and focus the left eyepiece by rotating the rubber grip ring
on the eyepiece holder it until the image appears clearest.
Then cover your left eye (or cover the left objective lens
of the binocular) and focus the right eyepiece by rotating
the eyepiece holder until the image appears clearest. The
binoculars are now focused. If you want to view an object
at a different distance, re-focusing of both eyepieces is
required. Also, changing eyepieces may require some slight
refocusing.
For astronomical observation, all objects will always appear
focused at the infinity focus point. This means you only
need to focus the binoculars once per observing session.
This also means you can take note of the diopter scale
(Figure 1) setting for each eyepiece when focused on an
astronomical object, and return to those settings when
observing another night. You will find this to be a great
convenience!
Congratulations on your purchase of a pair of quality Orion binoculars. The BT70 Binocular Telescope provides the
large light grasp you need for astronomical observation, but unlike a telescope, allows you to use both eyes simultaneously
for viewing. This results in better image resolution, contrast, and brightness than a similar sized telescope can provide.
WARNING Never look directly at the Sun
through your binoculars without professionally
made solar filters, even for an instant, or
permanent eye damage could result. Young
children should use these binoculars on sunny
days only with adult supervision.