National Geographic NG55CS Guide de démarrage rapide

NG55CS

Maksutov-Cassegrain

Telescope

Instructions

and

Owner’s Manual

Manual Part #: 264966

Introduction

Congratulations on your purchase of a precision-crafted NATIONAL GEOGRAPHIC™

telescope. With proper care and handling of your telescope, you will enjoy the pleasure

of looking at nature’s wondrous sights through the eye of this instrument for many

years.

Your new Maksutov-Cassegrain telescope provides you with the clarity and contrast of

a lens type (refractor) telescope and the brightness and color fidelity of a mirror type

(reflector) telescope. And it all comes in an easy-to-use, compact package.

As a terrestrial (land) telescope, the NG55CS delivers great views of mountains,

valleys, wildlife, and many other wonders and features of the world around us. Its

compact size and light weight make it an ideal telescope for hikers, travelers, cottagers,

and anyone else who demands superior optical performance in a small telescope.

As an astronomical telescope your NG55CS will reward you with excellent views of

lunar detail, Jupiter’s four largest “Galilean” moons, and even Saturn’s rings.

To obtain the best performance from your telescope, please read this manual carefully

and completely.

WARNING!

CHOKING HAZARD

Small parts. Not suitable for

children under 3 years.

WARNING!

NEVER aim your telescope at the sun or even close to the sun!

Instant and irreversible damage can occur,

including blindness!

Do not let children use any telescope without adult supervision.

SETUP:

1) Position the telescope and the tripod so that the ¼” x 20 tripod bolt is aligned with

the tripod socket underneath the telescope tube (1). Hand-tighten the tripod bolt

by turning it clockwise. Do not over-tighten.

2) Spread the three tripod legs and set the unit down on a level surface.

3) You can adjust the height of the telescope by loosening the ring (2) around the

center column of the tripod and moving the telescope up and down. When the

telescope is in the proper position re-tighten the ring.

4) To make small directional changes there are two micrometric adjustments. The

vertical adjustment (3) is located at the rear of the tripod head and the lateral

(side-to-side) adjustment (4) is located on the side of the tripod head.

Note: Because these are fine motion adjustments they have limited movement

ranges. If you cannot turn an adjustment knob, do not force it. You have reached the

limit of the adjustment. You must turn the knob in the opposite direction 4 or 5 times.

Then re-position the tripod to aim the telescope at the subject being observed. You

will find that you have regained fine motion adjustment.

5) To make a large vertical adjustment, loosen the large knob (5), adjust the

telescope, and then re-tighten the large knob.

ZOOM and FOCUS:

1) Your telescope is equipped with a 30X-90X zoom eyepiece* (6). To change the

magnification power, gently turn the rubber zoom ring (7) on the eyepiece. The

magnification power is indicated on the side of the eyepiece.

* Some models may be equipped with zoom eyepieces with a 15X-45X power

range or a 20X-60X power range.

2) Set the eyepiece to its lowest magnification.

3) Turn the rubberized focusing knob (8) until you see the clearest image. The focus

adjustment actually moves the rear mirror inside your telescope. This precision

adjustment gives you the ability to make extremely fine focus adjustments.

4) To see your subject at a higher magnification, turn the zoom ring (7) on the

eyepiece. You will have to re-adjust the focusing knob (8).

5) Note that as the zoom power increases, the brightness of the image decreases.

This is quite normal. To observe in low light situations you will find the lower

zoom powers perform better.

USING YOUR TELESCOPE FOR ASTRONOMICAL VIEWING

1) Take your telescope outside. We do not recommend viewing objects through a

window. Your view can be distorted by reflections in the glass of a closed window or

by air currents of differing temperatures passing through an open window.

2) Allow your telescope to adjust to the outside temperature. Your telescope will

perform much better if the temperature of the lenses and the air inside the tube are

the same as the outside temperature. We recommend that you allow 30 minutes to

equalize the temperatures when the difference in temperature difference is extreme.

If you try to use the telescope before it has adjusted to the outdoor temperature you

may find it somewhat difficult to focus accurately.

3) Find a location away from any direct light source. If you live in a large town or city,

your viewing will probably improve the farther you move away from the ‘light

pollution’ of city lights. The sky glow of a town or city can dramatically reduce the

telescope’s performance and viewing capabilities.

4) Remove the round plastic dust cover (lens cap) from the front of your telescope.

5) We strongly recommend that you begin your viewing session with the 30X zoom

power. It will give you the widest angle and the brightest, sharpest view.

When possible, avoid sudden temperature changes, as the moisture in the air may

condense as water droplets (dew) on the objective lens. If dew forms on your objective

lens do not wipe it off. Take your telescope indoors and follow Step 2 – below on this

page.

CARE AND CLEANING OF OPTICS

Optical components of a telescope get dirty over time. Dirt or dust on a lens should be

removed with the utmost care. A considerable amount of dirt or dust would have to

accumulate on the optical surface before your view would be compromised.

1) Keeping the dust cap on during storage and transport and keeping the telescope in

its case will reduce dust collection.

2) Condensation may collect on the optical surfaces when the telescope is not in use.

Remove the dust cap and allow the moisture to evaporate naturally. Point the telescope

downward to minimize the accumulation of airborne dust.

3) Once all moisture has evaporated, replace the dust cap.

3) Filtered, compressed air may be used to remove surface dust from lenses and

mirrors. Remove the dust cap. Once removed, point the can away from the lens and

gently expel some air and any condensation or dust that has accumulated on the

discharge tube. Spray the lens with short bursts of air to carefully remove the dust

particles. DO NOT HOLD THE TRIGGER OF THE COMPRESSED AIR CAN FOR

EXTENDED PERIODS BECAUSE PROPELLANT FROM THE CAN MIGHT

ESCAPE AND DAMAGE THE OPTICAL SURFACE.

If, after several attempts, you cannot remove the particles, take the telescope to an

optical professional for cleaning.

If you keep the dust cap on your telescope when it is not in use and avoid handling the

lenses, only minimal optical maintenance of your telescope should be required.

WHAT TO LOOK FOR IN THE NIGHT SKY

There is a whole universe of objects you could view at night, so where do you start?

We recommend starting with the most prominent objects first.

The moon

The moon is the easiest target to find at night. When the moon is in full position, it

bathes the night with a silvery light that washes the sky of all but the brightest objects.

The best time to view the moon is not when it is full, but rather when it is less than half

full. The dividing line between dark and light on the moon, called the terminator, shows

the best detail in the craters and mountains.

The planets

The planets, our solar system companions, range in size and substance from moon-size

rocky bodies to giant gas balls, which could hold Earth 1,000 times over. To find the

planets, you will need information about their times of visibility. An astronomy magazine

will give you the locations of the planets as they change position from month to month.

The Internet is also an excellent source of information, offering star charts, maps, and

more!

The popular and more familiar constellations often provide the easiest landmarks to

help find the planet’s locations and paths of orbit. Most people have looked up at the

sky at night and seen some of the planets without even realizing it. A planet looks like a

bright star but does not twinkle like a star does; it looks like a tiny ball. Venus, Mars,

Jupiter, and Saturn are the easiest planets to view. Mercury is dimmer, usually below

the horizon, and more challenging to find.

Each of the planets provides interesting views. Venus is covered with clouds so all that

is visible is an extremely bright light, the brightest next to the moon. However, Venus,

like the moon, goes through phases. As it travels around the sun, different areas of its

surface are illuminated, producing crescent shapes of varying sizes. Mars is the red

planet. When it is above the horizon, it is noticeably red and stands out like a beacon in

the night sky. The apparent brightness of Mars varies as the planet orbits around the

sun and throughout its period of visiblity, it will look brighter or dimmer depending on its

distance from Earth.

Jupiter is the largest planet in our solar system and the second brightest next to Venus.

Jupiter has many moons, four of which are often visible through your telescope when

viewing conditions permit. As you watch them throughout the evening, you will see that

they change position relative to each other and to Jupiter. It is possible with careful

planning to actually see one of the moons disappear either in front of or behind Jupiter

as it orbits around the planet.

Saturn, the second largest planet, is not as bright as Jupiter and so its moons are not as

visible through small telescopes. The large rings that encircle Saturn are spectacular to

observe, however.

FREQUENTLY ASKED QUESTIONS

1) How far can I see?

If you stand outside and look up at the night sky on a clear evening, you can see

hundreds of stars without the aid of your telescope. The telescope is a light-gathering

instrument that magnifies the view—providing significantly more detail and unveiling

more stars, nebulae, and celestial objects. With the aid of a telescope, you will be able

to enjoy exciting views of Saturn’s rings, Jupiter’s major moons, the Orion Nebula, and

much more.

2) Why can’t I see anything through my telescope?

If you see only gray or black when looking through your telescope, even after searching

for an object to view, it is very likely that you are using a zoom power that is too

powerful. To solve this problem always start with the lowest power first, and only zoom

to the higher powers after you have located an object.

3) When I use my highest zoom power, everything looks much darker. Why?

As magnification in a telescope increases, brightness diminishes. Conversely,

brightness increases when magnification is reduced. If an image appears too dark or

unclear, use a lower power. Views of small, bright objects are superior to those of large,

dark, or blurry ones! Atmospheric conditions, air currents, as well as light and air

pollution also affect viewing quality.

4) As I look through my telescope, objects in the sky appear to move. Why is

that?

When you observe an astronomical subject through a telescope, the constant rotation of

the Earth makes things appear as though they are moving across the viewing area. If

you would like to reduce this effect of movement to a minimum and observe the widest

field of view, you should use lower zoom power.

WARNING! CHOKING HAZARD –

Small parts. Not suitable for children

under 3 years.

Made in China

Manual Part #: 264966

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