National Geographic 9621502 Mode D'emploi page 10

Earth Observation
When viewing terrestrial objects, look through the heat waves that form over
the Earth's surface. You may have seen these heat waves shimmering across the
asphalt in the summer. Heat waves cause a loss of image quality.
If heat waves are affecting their vision, try focusing out a bit to get a smoother,
better quality image. Use the early morning hours for your observations, before
the earth's surface has heated up too much.
Cleaning and maintenance
Your spotting scope is a precision optical instrument built to provide a lifetime
of observing experience. (It will rarely, if ever, require repair or maintenance by
the manufacturer.) Follow this guideline to keep your spotting scope in the best
condition:
› Avoid cleaning the lenses of the spotting scope. A little dust on the surface of
the corrective lens will not result in any loss of image quality.
› If absolutely necessary, dust should be removed from the front lens very
carefully with a camel hair brush or blown away with an ear syringe (available
at most pharmacies).
› Fingerprints and organic materials on the front lens can be removed with a
solution of 3 parts distilled water and 1 part isopropyl alcohol. You can also
add 1 drop of biodegradable dishwashing liquid per half liter of solution. Use
soft, white face wipes and make short, gentle movements. Change the wipes
frequently.
10
ATTENTION: Do not use perfumed cloths or cloths with lotions.
These could damage the optics.
› Your spotting scope is rainwater protected: This means that it is suitable
to be used by a sportsman, a sailor or an occasional user in an environment
where the spotting scope may be exposed to water, e.g. rain, fog, spray, etc. It
is designed to be resistant if accidentally exposed to water, but it is not suitable
for diving or extensive use in water. If your spotting scope is intentionally
submerged in water for a long period of time, you risk voiding your warranty.
Also note that although your spotting scope can be used near water, water on the
lens will cause distortion of the images. Wipe the water off the entire unit with a
soft cloth when you move away from the water again.