Levenhuk Ra 200N F4 Carbon OTA - Manual (Page 4)

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Batteries safety instructions
Operating the telescope
• Always purchase the correct size and grade of battery most suitable for the intended use.
• Always replace the whole set of batteries at one time; taking care not to mix old and new ones, or batteries of different types.
• Clean the battery contacts and also those of the device prior to battery installation.
• Make sure the batteries are installed correctly with regard to polarity (+ and -).
• Remove batteries from equipment that is not to be used for an extended period of time.
• Remove used batteries promptly.
• Never attempt to recharge primary batteries as this may cause leakage, fire, or explosion.
• Never short-circuit batteries as this may lead to high temperatures, leakage, or explosion.
• Never heat batteries in order to revive them.
• Remember to switch off devices after use.
• Keep batteries out of the reach of children, to avoid risk of ingestion, suffocation, or poisoning.
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 im-
ages as a result. The fan is powered by 8 AA batteries (not included in the kit), or an external 12V battery. Please allow addi-
tional 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. Just insert it into the focuser and tighten 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 com-
pletely 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 correc-
tor (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.
Model Levenhuk Ra 200N F4
Carbon OTA
Levenhuk Ra 200N F4
OTA
Levenhuk Ra 200N F5
OTA
Levenhuk Ra 250N F4
OTA
Optical tube material carbon fiber metal
Optical design Newtonian reflector
Primary mirror diameter
(aperture), mm
200 200 200 250
Focal length, mm 800 800 1000 1000
Focal ratio f/4 f/4 f/5 f/4
Optics material BK-7 optical glass
Optics coating quartz-protected aluminum
Focuser 2'' dual-speed Crayford
Finderscope optical, 8x50 mm
Tube-mount assembly system dovetail plate
Tube length, in / mm 30.3 / 770 28.3 / 720 37 / 940 38.6 / 980
Tube diameter, in / mm 9.4 / 240 9.4 / 240 9.4 / 240 12.2 / 310
Tube weight, lbs / kg 13.8 / 6.3 16 / 7.3 18.2 / 8.3 29.3 / 13.3
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