Meade DS-2000 Series, Инструкция по эксплуатации

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13
Choosing an Eyepiece
A telescope’s eyepiece magnifies the light gathered by the optical tube. Each eyepiece has a
focal length, expressed in millimeters, or “mm.” The smaller the focal length, the higher the
magnification. For example, an eyepiece with a focal length of 9mm has a higher magnification
than an eyepiece with a focal length of 25mm.
Your telescope comes supplied with a low-powered 25mm or 26mm eyepiece which gives a
wide, comfortable field of view with high image resolution. Always begin your observations with
this eyepiece.
Low power eyepieces offer a wide field of view, bright, high-contrast images, and eye relief dur-
ing long observing sessions. After an object is located and centered in the eyepiece, try switch-
ing to a higher power eyepiece to enlarge the image.
NOTE:
Viewing conditions vary from night-to-night and from site-to-site. Turbulence in
the air, even on an apparently clear night, can distort images. If an image appears
fuzzy and ill-defined, return to a lower power eyepiece for a more well-resolved image.
The power, or magnification of a telescope is determined by the focal length of the telescope
and the focal length of the eyepiece being used. To calculate eyepiece power, divide the tele-
scope's focal length by the eyepiece's focal length. For example, you may wish to use a 25mm
eyepiece with the DS-2000 model DS-2114S. Look up the focal length of the DS-2114S under
SPECIFICATIONS: DS-2114S
, page 32. The focal length is listed as 1000mm.
Telescope focal length divided by Eyepiece focal length = Eyepiece power
1000 25 = 40
The eyepiece power, or magnification is
therefore 40X (approximately).
The Barlow Lens
Some Meade telescopes include a power
multiplier called a Barlow lens. Consisting of
a lens mounted in a 4"-long (10cm) tube,
the Barlow doubles or triples the power
obtained when an eyepiece is used alone.
In the example above, a 25mm eyepiece
results in 40X magnification with the DS-
2114S telescope; when this same eyepiece
is used in conjunction with a 2x Barlow lens,
power is doubled to 80X. To use the Barlow,
insert it into the diagonal prism (
refractor
models only) or eyepiece holder, followed
by the eyepiece.
NEVER
point the
telescope
directly at
or near the Sun at any
time! Observing the
Sun, even for the
smallest fraction of a
second, will result in
instant and irre-
versible eye damage,
as well as physical
damage to the tele-
scope itself.
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.
DS-2000 TIPS
Too Much Power?
Can you ever have too much power? If you’re
referring to eyepiece power (magnification),
yes, you can! The most common beginner’s
mistake is to “overpower” a telescope by
using too high of a magnification, which the
telescope’s aperture and atmospheric condi-
tions cannot reasonably support. Keep in
mind that a smaller, but bright and well-
resolved image is far superior to one that is
larger, but dim and poorly resolved (see
below). Powers above 200X should be
employed only under the steadiest atmos-
pheric conditions.
Autostar can calculate the best eyepiece for
you to use. Try out the “Eyepiece Calc” fea-
ture in the Utilities menu.
Most observers should have three or four
additional eyepieces to achieve the full range
of reasonable magnifications possible with
the DS-2000 telescopes. See “OPTIONAL
ACCESSORIES,” page 28.
Fig. 14a & 14b: Jupiter; example of too much
magnification.
Fig. 13: To change the red
dot's brightness intensity,
rotate the intensity knob.
Fig. 15: 25mm and
9mm eyepieces.
Intensity Slider