To install an optional eyepiece:
1. Loosen the screw on the focuser.
2. Slide the eyepiece into the focuser.
3. Retighten the screw to secure the eyepiece in place.
Operating the telescope
Levenhuk Ra reflectors are designed primarily for astrophotography, but they may be used for visual observations as well.
We recommended using high-quality eyepieces for visual observations to achieve exceptional quality of produced views.
Cooling Fan
Your new reflector comes with a cooling fan built into the rear end of the optical tube. This fan reduces the time it takes the
primary mirror to adapt to the outside temperature. This eliminates fogging, and your OTA will produce sharper and brighter
images as a result. The fan is powered by 6 AA batteries (not included in the kit), or an external 12V battery. Please allow
additional time for cooling if there is a substantial difference between the indoor and outside temperatures. Once the telescope
has adapted to the outside temperature, you can turn off the cooling fan to reduce vibration of the optical tube.
Visual observations
To achieve focus, you will likely have to use the included 35-mm extension ring
the two thumbscrews to secure the extension ring in place. You can then use either a 2" eyepiece or a 1.25" eyepiece
(with a 1.25" adapter).
Focusing
One of the exciting new features of Levenhuk optical tubes is the inclusion of the new dual-speed Crayford focuser. Unlike the
traditional Crayford focuser with a spring-loaded shaft to hold the focus tube, the new linear ball bearing focuser allows you to
easily use heavier accessories, such as larger eyepieces, cameras, imagers, guiders, etc. It also reduces image shake and
completely eliminates backlash.
During celestial observations, out-of-focus images of dim stars may be very diffuse, making it difficult to focus on such objects.
Choose a brighter celestial body (such as the Moon) as your first observation object, and focus your view. With a 10:1 fine focus
adjustment (meaning that 10 turns of the fine focus knob equal 1 turn of the coarse focus knob) you can adjust the focus of your
view with great precision. Use the coarse focus knob to adjust the view until your object is as close to focus as possible, and
then make fine adjustments with the fine focus knob.
Astrophotography
Levenhuk Ra reflectors have high-quality BK-7 glass optics, which produce bright images and provide for fast exposure. However,
fast optics also inherently produce some coma, so to achieve the best possible images, it is recommended to use a coma
corrector (not included in the kit). The coma corrector may be attached to the focuser in front of the camera body. Coma
correctors eliminate coma and improve the quality of the resulting images across the field of view, so you do not have to crop
the images you have taken during your astrophotography sessions.
Camera assembly
Most CCD cameras have a 1.25" or 2" barrel, which means that you can attach them directly to the focuser, without an adapter.
Simply insert the nosepiece of the CCD camera into the focuser and lock it in place with the two thumbscrews.
To attach a DSLR camera, you will need an appropriate T-ring and a camera adapter. Simply attach the T-ring to the camera body
and thread the camera adapter onto the T-ring, insert the barrel of the camera adapter into the focuser and secure it in place
with the two thumbscrews.
Specifications
Optical design
Optics material
Optics coating
Primary mirror shape
Primary mirror diameter (aperture), mm
Focal length, mm
Focal ratio
Highest practical power, x
Focuser
Eyepiece barrel diameter
Tube-mount assembly system
3
. Just insert it into the focuser and tighten
Levenhuk Ra 200N F5 OTA
Newtonian reflector
BK-7 glass
aluminum 92~96% coating
paraboloid
200
1000
f/5
400
2'' dual-speed Crayford
1.25/2''
dovetail plate, tube rings
4