Meade Instruments Polaris Series - Manual (Page 20)

objects 100 times.
You can calculate how much
magnification an eyepiece will have with
your specific telescope. Just divide the
telescope focal length by the focal length of
the eyepiece.
Focal Length of the Telescope
÷
Focal Length of the Eyepiece
=
Magnification
Look at the specifications. For example, you
will see that the focal length of the Polaris 90
is 900mm. Let’s say that you have obtained a
6.3mm eyepiece. You can tell what the focal
length of your eyepiece is as it is always
printed on the side of the eyepiece. Divide:
900mm ÷ 6.3mm, which equals 142.86.
Round this off to the nearest whole number
and you find the 6.3mm eyepiece used with
the Polaris 90 magnifies objects 143 times.
If you use a Barlow lens with one of your
eyepieces, it doubles the magnification of
your eyepiece. Other types of Barlows
It will rarely, if ever, require factory servicing
or maintenance. Follow these guidelines to
keep your telescope in the best condition:
•As with any quality instrument, lens or mirror
surfaces should be cleaned as infrequently
as possible. Front surface aluminized mirrors
(reflecting models), in particular, should be
cleaned only when absolutely necessary. In
all cases avoid touching any mirror surface.
A little dust on the surface of a mirror or lens
causes negligible loss of performance and
should not be considered reason to clean
the surface. When lens or mirror cleaning
does become necessary, use a camel’s hair
brush or compressed air gently to remove
dust. If the telescope’s dust cover is replaced
after each observing session, cleaning of the
optics will rarely be required.
•Fingerprints and organic materials on
the lens or mirror may be removed with a
solution of 3 parts distilled water to 1 part
isopropyl alcohol. You may also add 1 drop
of biodegradable dishwashing soap per pint
of solution. Use soft, white facial tissues and
make short, gentle strokes. Change tissues
often.
CAUTION: Do not use scented or lotioned
can triple or further increase the power of
an eyepiece. To find out how much your
magnification is when you use a 2x Barlow,
multiply your eyepiece’s magnification by two.
For example, the 25mm low-power eyepiece
used with the Polaris 90 magnifies an object
36 times. Multiply 36 by 2 and you get 72
times magnification with a Barlow.
Eyepiece’s magnification x 2
=
Magnification with a 2X Barlow lens
It’s worth repeating: Keep in mind that a
bright, clear, but smaller image is more
interesting than a larger, dimmer, fuzzy one.
Using too high a power eyepiece is one
of the most common mistakes made by
new astronomers. So don’t think that higher
magnification is necessarily better—quite
often the best view is with lower magnification
value!
TAKING CARE OF YOUR TELESCOPE
Your telescope is a precision optical instrument
designed for a lifetime of rewarding viewing.
Looking at or near the Sun will cause irreversable damage to your eye. Do not point this telescope at or near the Sun. Do not look through the telescope as it is moving.
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