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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 mag-

nification.

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 po

wer 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 33. The focal length is listed as 1000mm.

Telescope focal length divided by Eyepiece focal length = Eyepiece power

1000 v 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.

OBSERVING

Observing by Moving the Telescope Manually

If you wish to observe a distant land object, such as a mountain top or a bird, you can observe

y merely pointing the telescope and looking through the e

yepiece.

Loosen the telescope’

s tr

ipod base lock knob (

26,

Fig.

) and Altitude loc

k (

Fig.

), so

that the telescope can mo

ve freely.

oint y

our telescope at distant street signs

, mountains

, trees, and other structures. Use

Smar

tfinder

to help site-in on an object.

3. Center the object using Smartfinder and then in the telescope eyepiece. When the object

centered in y

our e

epiece, re-tighten the base and Altitude locks.

4. Practice focusing objects with the focus knob (

1, Fig. 1).

5. Once you get a feel for how your telescope moves and focuses, try to view something more

challenging, like a bird or a distant moving train.

ou can also observe stars and objects in the night sky using this method, but note that objects

begin to slowly drift across the eyepiece field. This motion is caused by the rotation of the Earth.

As you become familiar with the Autostar handbox operation, you can counteract the drift using

the automatic tracking feature in the Autostar Setup menu (see

TO TRACK AN OBJECT AUTO-

TICALLY

, page 18), or b

y using Autostar's GO TO capabilities (see

TO SATURN

, page 19).

Impor

tant Note:

When

you look through your

telescope’

s eyepiece,

the image might look

str

ange at first.

If y

ou have a

refracting

telescope

, objects will

appear right-side-up, but

reversed left-for-right.

This will not make a

difference when

observing astronomical

objects, and in fact, all

astronomical telescopes

present inverted images.

During terrestrial

observing, when a

corrected image (right-

side up and correct left-

for-right) is desirable, an

optional Meade 45°

Erecting Prism is

available. See the

OPTIONAL

ACCESSORIES, page

29, or consult the

Meade Telescope

Catalog.

No means of correcting

the image is available for

reflecting telescopes—

the image will appear

upside down and

reversed left-for-right.

1 2 ... 9 10 11 12 13 14 15 16 17 18 19 ... 47 48

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