Meade Telescope ETX 90EC User Manual

Instruction Manual

ETX-90EC Astro Telescope

ETX-105EC Astro Telescope

ETX-125EC Astro Telescope

Meade Instruments Corporation

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CONTENTS

Quick-Start Guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4

WARNING!

Telescope Electronic Controller Functions . . . . . . . . .5

ETX: Your Personal Window on the Universe . . . . . . .6

Telescope Controls . . . . . . . . . . . . . . . . . . . . . . . . . .6

Electronic Controller Functions . . . . . . . . . . . . . . . . . .8

Never use a Meade ETX Astro Telescope

to look at the Sun! Looking at or near the

Sun will cause instant and irreversible

damage to your eye. Eye damage is often

painless, so there is no warning to the

observer that damage has occurred until it is

too late. Do not point the telescope or its

viewfinder at or near the Sun. Do not look

through the telescope or its viewfinder as it is

moving. Children should always have adult

supervision while observing.

Getting Started . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9

Parts Listing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9

Assembly Instructions . . . . . . . . . . . . . . . . . . . . . . . .9

Using the Viewfinder . . . . . . . . . . . . . . . . . . . . . . . .10

Focusing the Viewfinder . . . . . . . . . . . . . . . . . . .10

Aligning the Viewfinder . . . . . . . . . . . . . . . . . . . .10

Observation Techniques . . . . . . . . . . . . . . . . . . . . . . .11

Choosing an Eyepiece . . . . . . . . . . . . . . . . . . . . . . .11

Understanding Magnification . . . . . . . . . . . . . . . . . .12

Terrestrial Observing . . . . . . . . . . . . . . . . . . . . . . . .12

Astronomical Observing . . . . . . . . . . . . . . . . . . . . . .13

Sidereal Rate . . . . . . . . . . . . . . . . . . . . . . . . . . .13

The Electronic Controller . . . . . . . . . . . . . . . . . . . . .13

Slew Speeds . . . . . . . . . . . . . . . . . . . . . . . . . . .13

Modes of Operation . . . . . . . . . . . . . . . . . . . . . .14

Telescope Mountings . . . . . . . . . . . . . . . . . . . . . . . .14

Alt/Az Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . .14

Polar Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15

Celestial Coordinates . . . . . . . . . . . . . . . . . . . . .16

Locating the Celestial Pole . . . . . . . . . . . . . . . . .16

Polar Alignment Procedure . . . . . . . . . . . . . . . . .16

CAUTION!

Use care to install batteries as indicated by

the battery compartment. Follow battery

manufacturer's precautions. Do not install

batteries backward or mix new and used

batteries. Do not mix battery types. If these

precautions are not followed, batteries may

explode, catch fire, or leak. Improperly

installed batteries void your Meade warranty.

Photography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18

A Few Tips on Photography . . . . . . . . . . . . . . . . . . .19

Optional Accessories . . . . . . . . . . . . . . . . . . . . . . . . .20

General Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . .22

Storage and Transport . . . . . . . . . . . . . . . . . . . . . . .22

Inspecting the Optics . . . . . . . . . . . . . . . . . . . . . . . .23

Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . .23

Meade Customer Service . . . . . . . . . . . . . . . . . . . . .24

Telescope Specifications . . . . . . . . . . . . . . . . . . . . .25

If you are anxious to use your ETX Astro

Telescope for the first time, before a

thorough reading of this instruction manual,

see the QUICK-START GUIDE on page 4.

Appendix A: Advanced Controller Functions . . . . . . .26

Tracking Motor Speed . . . . . . . . . . . . . . . . . . . . . . .26

Changing Modes . . . . . . . . . . . . . . . . . . . . . . . . . . .26

Appendix B: Helpful Charts . . . . . . . . . . . . . . . . . . . .27

Latitude Chart for Major Cities of the World . . . .27

Star Locator . . . . . . . . . . . . . . . . . . . . . . . . . . . .27

Appendix C: Polar Alignment; Setting Circles . . . . . .28

Precise Polar Alignment . . . . . . . . . . . . . . . . . . .28

Setting Circles . . . . . . . . . . . . . . . . . . . . . . . . . .28

Appendix D:You and the Universe . . . . . . . . . . . . . . .29

Objects in Space . . . . . . . . . . . . . . . . . . . . . . . . . . .29

The Moon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29

Planets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29

Deep-Sky Objects . . . . . . . . . . . . . . . . . . . . . . . .30

® The name “Meade,” the Meade logo, and “ETX” are

trademarks registered with the U.S. Patent Office and in

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QUICK-START GUIDE

Remove the ETX from its packaging and place it on a

sturdy surface. Place the eyepiece (A) and viewfinder

(B) into their appropriate positions on the telescope

and tighten their respective attachment screws to a

firm feel only.

Slide the Power Switch (E) on the Computer Control

panel to the ON position. The lights flicker on the

Electronic Controller. Press any key and the motors

briefly move the telescope. The Electronic Controller is

now operational.

Slew Speed:

Fast

Medium

Moderate

Slow

Securely place the ETX on its side and remove the

battery compartment cover (C) from the underside of

the drive base. Insert eight (user-supplied) AA-size

batteries into the battery compartment (D) in the

proper orientation. Replace the cover and return the

telescope to an upright position.

Use the Electronic Controller Arrow keys (H) to move

the telescope up, down, left, and/or right. To change

the telescope’s slew speed, press the SPEED key (I).

The indicator lights signify the speed, with the upper

light showing the highest speed. Each press slows the

speed down one level, then cycles back to the highest

speed.

NOTE: Before

NOTE: The

observing, verify

telescope has

rotational hard

stops in the

that the flip-mirror

control (14, Fig. 1)

is in the “up”

horizontal and

vertical axes to

prevent damage to

the telescope. See

page 6, for more

information.

position. See FLIP-

MIRROR CONTROL,

page 7, for more

information.

Verify that the Computer Control panel power switch (E)

is in the OFF position. Remove the Electronic Controller

(F) from the packing materials and plug it into the HBX

port (G). Tighten the vertical and horizontal locks (6 and

9, Fig. 1) and then remove the dust cover (19, Fig. 1)

from the end of the telescope tube.

Sight along the side of the telescope’s main tube to

locate an object. Practice using the Electronic

Controller Arrow keys to center an object in the

telescope’s field of view. Use the telescope’s focus

knob (8, Fig. 1) to bring the object into focus.

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TELESCOPE AND ELECTRONIC CONTROLLER FUNCTIONS

Features of the ETX-90EC, ETX-

105EC, and ETX-125EC are

identical, with the exception of

the size of optical tube and the

type of viewfinder included as

standard equipment.

(on left

fork arm)

Fig. 1: The ETX-90EC Astro Telescope.

Fig. 1 (Inset): Computer Control Panel. (A) On/Off switch;

(B) Auxiliary ports; (C) Handbox port; (D) 12v connector; (E)

Power indicator light.

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ETX:Your Personal Window to the Universe

The Meade ETX-90EC, ETX-105EC, and the ETX-125EC are extremely versatile, high-resolution

telescopes with features similar to those once available only with larger and more specialized imaging

systems. With pushbutton controls, automatic tracking of celestial objects (with one of the optional tripods),

and diffraction-limited imaging, an ETX telescope may be all the telescope ever required by many terrestrial

and astronomical observers.

Your ETX telescope reveals nature in an ever-expanding level of detail. Observe the feather structure of an

eagle from 50 yards or study the rings of the planet Saturn from a distance of 800 million miles. Focus

beyond the Solar System and observe majestic nebulae, ancient star clusters, remote galaxies, and even

stars recently discovered to have planets orbiting about them. Meade ETX telescopes are instruments fully

capable of growing with your interest and are ideal for both the casual observer and serious astronomer

alike.

Telescope Controls

An important array of features and manual controls facilitates operation of an ETX telescope. Be sure to

become acquainted with all of these controls before attempting observations through the telescope.

ᕡ

ᕢ

Eyepiece - Place the supplied SP 26mm eyepiece into the 90° Eyepiece Holder (4, Fig. 1) and tighten in

place with thumbscrew (3, Fig.1).

Viewfinder -

a. ETX-90EC

8 x 21mm Viewfinder: Slide the eyepiece end of the viewfinder through the front of

the viewfinder bracket (1, Fig. 5).

b. ETX-105EC, ETX-125EC 8 x 25mm Right-Angle Viewfinder: Slide the front cell end of the

right-angle viewfinder through the rear of the viewfinder bracket (2, Fig. 5).

Eyepiece Holder Thumbscrew - Tightens the eyepiece in place. Tighten to a firm feel only.

90° Eyepiece Holder - Holds the eyepiece upright for easy viewing.

ᕣ

ᕤ

ᕥ

Optical Tube - The main optical component that gathers the light from distant objects and brings this

light to a focus for examination with the eyepiece.

ᕦ

Vertical Lock - Controls the manual vertical movement of the telescope. Turning the vertical lock

counterclockwise unlocks the telescope enabling it to be freely rotated by hand about the vertical axis.

Turning the vertical lock clockwise (to a firm feel only) prevents the telescope from being moved

manually, but engages the vertical motor drive clutch for Electronic Controller operation. When polar

aligned, the vertical lock serves as the Declination, or Dec. lock (see DECLINATION, page 16).

Note: The vertical lock knob is a knurled knob located on the fork arm to the right of the focus

knob (8, Fig. 1). Mounted beneath the knob is a circular scale with no numbers. Do not confuse

this scale with the Dec. setting circle (16, Fig. 1) on the opposite fork arm which has a

numbered scale used to locate astronomical objects.

CAUTION: When loosening the vertical lock, be sure to support the optical tube (5, Fig. 1).The

tube may swing downward suddenly and damage the telescope.

ᕧ

Fork Arms - Hold the optical tube in place.

Note: The telescope base and fork mount are designed with internal “rotational limit stops.”

The horizontal limit stop prevents the telescope from rotating more than 360° to avoid damage

to the internal wiring. The vertical limit stop prevents the viewfinder from contacting the fork

mount when the telescope is pointed upward just past 90° and prevents the optical tube from

contacting the base if pointed downward more than 30°. Do not force the telescope to move

beyond these stops or damage to the telescope will result.

ᕨ

ᕩ

Focus Knob - Moves the telescope’s optical tube (5, Fig. 1) in a finely-controlled motion to achieve

precise image focus. The ETX telescopes can be focused on objects from a distance of about 11.5 ft

(ETX-90EC) or 15 ft (ETX-105EC or ETX-125EC) to infinity. Rotate the focus knob clockwise to focus

on distant objects, and counterclockwise to focus on nearby objects.

Horizontal Lock - Controls the manual horizontal rotation of the telescope. Loosen the horizontal lock

counterclockwise to unlock the telescope, enabling it to be freely rotated by hand about the horizontal

axis. Tightening the horizontal lock clockwise prevents the telescope from being rotated manually, but

engages the horizontal motor drive clutch for Electronic Controller operation. When polar aligned, the

horizontal lock serves as the Right Ascension, or R.A. lock (see RIGHT ASCENSION, page 16).

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Computer Control Panel

A. ON/OFF Switch - Turns the Computer Control Panel and Electronic Controller ON or OFF.

Note: Always remove the batteries if they are not to be used for a long period of time.

B. Auxiliary (AUX) Ports (2) - Provide connection for current and future Meade accessories,

such as the Meade “AstroFinder Software with #505 Cable Connector Kit,” which allows you to

control your ETX from a PC. See OPTIONAL ACCESSORIES, page 20.

C. Handbox (HBX) Port - Plug the Electronic Controller or the optional #497 Autostar

handbox into this port.

D. 12v: The 12v connector is designed to accept an external power supply such as the

optional #541 AC Adapter or the #607 Power Cord (see OPTIONAL ACCESSORIES, page

20). When one of the external power supply options is used, the internal batteries are

disconnected from the power circuit.

E. LED - The red power indicator light illuminates when power is supplied to the connected

handbox and to the telescope’s motor drive.

Base Housing - Supports the telescope for placement on a flat, level surface, such as a tabletop or

optional tripod. See OPTIONAL ACCESSORIES, page 20.

Holes for Optional Tripod - See your tripod’s instruction sheet for mounting information.

Right Ascension (R.A.) Setting Circle - See page 28 for detailed information.

Flip-Mirror and Flip-Mirror Control Knobs - ETX telescopes include an internal mirror. With the flip-

mirror control in the “up” position, as shown in Fig. 2a, light is diverted to the eyepiece. With the flip-

mirror control in the “down” position, as shown in Fig. 2b, light proceeds straight out the photo port for

photography. See PHOTOGRAPHY, page 18.

Note: The flip-mirror control is in the “up” position when the control is vertical (perpendicular

to the telescope tube). To place the flip-mirror in the “down” position, turn the control until it is

horizontal.

Photo Port - Attach any 35mm camera with a removable lens to this port using an optional #64ST T-

Adapter or attach the #932 Erecting Prism for correctly oriented images through the eyepiece. See

OPTIONAL ACCESSORIES, page 20.

Declination (Dec.) Setting Circle (on left fork arm) - See page 28 for detailed information.

Viewfinder Alignment Screws -Adjust these screws to align the viewfinder. See pages 9 through 11

for more information.

Fig. 2a: Flip mirror

control in the “up”

position.

Viewfinder Alignment Bracket -Attach the viewfinder to this bracket. See pages 9 through 11 for

more information.

Dust Cap - Unthread the dust cap counterclockwise from the front lens of the telescope.

Note: The dust cap should be replaced after each observing session and the power turned off

to the telescope. Verify that any dew that might have collected during the observing session

has evaporated prior to replacing the dust cap. Do not overtighten.

Battery Compartment (not shown, underneath base) - Install eight user-supplied AA batteries in this

compartment. See page 9 for more information.

Fig. 2b: Flip mirror

control in the “down”

position.

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Electronic Controller Functions

ᕡ

Fast

ᕧ

ᕦ

Medium

Moderate

Slow

ᕢ

ᕣ

ᕥ

ᕤ

Fig. 3: Electronic Controller. (1) Arrow Keys; (2) Indicator

Lights; (3) SPEED Key; (4) Coil Cord; (5) MODE Key; (6) OUT

Key; (7) IN Key.

The Electronic Controller provides you with the means to control the telescope motors from a compact

handbox. The Electronic Controller (Fig. 3) has soft-touch keys designed to have a positive feel, even

through gloves.

The primary functions of the Electronic Controller are to move (slew) the telescope to an object, indicate the

slew speed, and to operate the optional #1244 (ETX-90EC or ETX-105EC) or #1247 (ETX-125EC) Electric

Focuser (see OPTIONAL ACCESSORIES, page 20). Other functions are also possible when using the MODE

key. A detailed description of the functions and operation of the Electronic Controller is found in ADVANCED

ELECTRONIC CONTROLLER FUNCTIONS, page 26.

ᕡ

Arrow Keys (1, Fig. 3): Press one of the four Arrow keys to slew the telescope (i.e., up, down, left,

and right) at any one of four slew speeds (see SPEED KEY below).

Important Note: If you reverse directions while using the Arrow keys to slew to objects, there

may be a slight pause as the telescope motors compensate for the reversal of the internal

gears.

Light No.

Light Status

ᕢ

ᕣ

Indicator Lights (2, Fig. 3): The four red LED (Light Emitting Diode) lights indicate the current slew

speed of the telescope.

Light 1

Note: For purposes of this manual, the lights are identified as 1 through 4, with 1 being the top light

and 4 being the bottom light.

Light 2

Light 3

Light 4

Blinking

Off

SPEED Key (3, Fig. 3): Press the SPEED key to change the speed at which the telescope slews to an

object. Each press of the SPEED key changes the slew speed to the next slower setting. If the controller

is already on the slowest slew speed (light 4), pressing the SPEED key cycles back to the highest speed

(light 1). Slew speeds are signified by the indicator lights (2, Fig. 3).

Indicator Light Key

The procedures in this manual

identify the status of the four

indicator lights as depicted

above: on, blinking, or off.

ᕤ

ᕥ

Coil Cord: Plug into the HBX connector of the Computer Control Panel.

MODE Key (5, Fig. 3): Press and hold the MODE key to place the Electronic Controller into the Mode

function (see APPENDIX A, page 26).

ᕦ

ᕧ

OUT Key (6, Fig. 3): When using the optional #1244 (ETX-90EC or ETX-105EC) or #1247 (ETX-

125EC) Electric Focuser (see OPTIONAL ACCESSORIES, page 20), press the OUT key to move the

focus point outward.

IN Key (7, Fig. 3): When using the optional #1244 (ETX-90EC or ETX-105EC) or #1247 (ETX-125EC)

Electric Focuser (see OPTIONAL ACCESSORIES, page 20), press the IN key to move the focus point

inward.

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GETTING STARTED

Parts List

ETX telescopes are assembled virtually

complete at the Meade factory. Getting the

telescope ready for first observations

requires only a few minutes. When first

opening the packing box, note carefully the

following parts:

• The ETX Astro Telescope with fork-

mount system.

• Electronic Controller with attached coil

cord.

• Viewfinder.

• Super Plössl (SP) 26mm eyepiece,

packed in a plastic storage container.

• Hex-wrench set (2 wrenches), packed

with the manual.

The viewfinder is packed separately from

the main telescope to avoid the possibility

of the viewfinder slipping in its bracket and

scratching during shipment.

Fig. 4: Bottom view of an ETX showing eight AA-size

batteries mounted inside the battery compartment.

(1) High-latitude tripod leg hole; (2) Drive base;

(3) Alternate tripod leg hole; (4) Release latches;

(5) Battery compartment cover; (6) Battery compartment.

Assembly Instructions

Assembly of your telescope requires the

following procedures: install batteries,

insert an eyepiece, attach the viewfinder,

and plug in the handbox.

Install the Batteries

Assembly of all three of the ETX model telescopes requires eight user-supplied AA-size batteries and the

following steps:

The telescope’s battery compartment (6, Fig. 4) is at the bottom of the drive base. Place the telescope

securely on its side as shown in Fig. 4. Open the battery compartment by simultaneously depressing the

two release latches (4, Fig. 4) and pulling the battery cover (5, Fig. 4) away from the drive base. Insert

eight AA-size batteries into the battery

compartment, oriented as shown on the

FOR BEGINNERS

battery mounting board. Slide and snap the

cover back in place. Return the telescope

to an upright position.

TIPS

Join an Astronomy Club

Attend a Star Party

One fun way to learn about astronomy is to join an

astronomy club. Check your local newspaper,

school, library, or telescope dealer/store to find out

if there’s a club in your area.

Insert an Eyepiece

Remove the SP 26mm eyepiece (1, Fig. 1)

from its container and place it in the

eyepiece holder (4, Fig. 1). Tighten the

thumbscrew (3, Fig. 1) to a firm feel only.

Plug in the Handbox

At club meetings, you will meet other astronomy

enthusiasts with whom you will be able to share

your discoveries. Clubs are an excellent way to

learn more about observing the sky, to find out

where the best observing sites are, and to compare

notes about telescopes, eyepieces, filters, tripods,

and so forth.

Be certain that the power switch on the

Computer Control panel (10A, Fig. 1) is in

the OFF position. Plug the coil cord of the

Electronic Controller into the HBX port

(10C, Fig. 1).

Attach the Viewfinder

ETX-90EC: 8 x 21mm Viewfinder: Slide

the eyepiece end of the viewfinder through

the front of the viewfinder bracket (1, Fig.

5).

Often, club members are excellent photographers.

Not only will you be able to see examples of their

art, but you may even be able to pick up some

“tricks of the trade” to try out on your ETX

telescope. See page 18 for more information about

photography with the ETX.

ETX-105EC or ETX-125EC: 8 x 25mm

Right-Angle Viewfinder: Slide the front

cell end of the right-angle viewfinder

through the rear of the viewfinder bracket

(2, Fig. 5).

Many groups also hold regularly scheduled Star

Parties at which you can check out and observe

with many different telescopes and other pieces of

astronomical equipment. Magazines such as Sky &

Telescope and Astronomy print schedules for many

popular Star Parties around the United States and

Canada.

Unthread the six alignment screws slightly

to fit the viewfinder through the bracket.

With the viewfinder in place, tighten the six

alignment screws to a firm feel only against

the viewfinder tube.

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Using The Viewfinder

As with most astronomical telescopes,

the ETX model telescopes present a

fairly narrow field of view to the observer.

As a result it is sometimes difficult to

locate and center objects in the

telescope’s field of view. The viewfinder,

by contrast, is a low-power, wide-field

sighting scope with crosshairs that let

you easily center objects in the eyepiece

of the main telescope’s field of view. The

telescope viewfinder is a great help in

locating faint astronomical objects before

you begin observing through the

telescope eyepiece.

ETX-90EC Viewfinder

ETX-105EC/-125EC Right-Angle Viewfinder

Fig. 5: Viewfinder Installation.

ETX-90EC 8 x 21mm Erect-Image Viewfinder:

Standard equipment with the ETX-90EC, the 8 x 21mm Erect-Image Viewfinder has 8-power magnification

and an aperture of 21mm. This viewfinder presents a correctly oriented image both up-and-down and

left-to-right.

ETX-105EC or ETX-125EC 8 x 25mm Right-Angle Viewfinder:

Standard equipment with the ETX-105EC and ETX-125EC, the 8 x 25mm Right-Angle Viewfinder has 8-

power magnification and an aperture of 25mm. This viewfinder presents a correctly oriented image up-

and-down, but is reversed left-for-right.

Focusing the Viewfinder

The ETX model viewfinders are pre-focused at the factory. Individual eye variations may require that the

viewfinder be re-focused. To check the focus, point the viewfinder at a distant terrestrial (land) object such

as a telephone pole or light pole and look through the viewfinder. If the viewfinder image is not in sharp

focus, follow the procedure below that applies to your telescope model.

ETX-90EC

1. Remove the viewfinder by slightly unthreading the six alignment screws (4 and 6, Fig. 6) and slipping it

out of the bracket.

2. Loosen the knurled lock-ring (2, Fig. 6) located near the viewfinder’s front lens cell (1, Fig. 6). Unthread

this ring (counterclockwise, as seen from the eyepiece-end of the viewfinder) by several turns.

3. Look through the viewfinder and focus on a distant object. Slowly rotate the front lens cell in one direction

or the other, until the object appears sharp. One or two rotations of the lens may have a significant effect

on image focus.

4. Lock the focus in place by threading the knurled lock-ring clockwise up against the viewfinder’s lens cell.

5. Replace the viewfinder into the viewfinder bracket. Gently tighten the six alignment screws. Proceed with

Aligning the Viewfinder.

ETX-105EC or ETX-125EC

Turn the focus ring (2, Fig. 6) at the base

of the viewfinder eyepiece (3, Fig. 6) in

either direction until a sharp focus is

reached.

Aligning the Viewfinder

ETX-125EC

In order for the viewfinder to be useful, it

must first be aligned with the main

telescope, so that both the viewfinder and

the main telescope are pointing at

precisely the same location. To align the

viewfinder:

1. Turn the three rear alignment screws

of the viewfinder bracket (6, Fig. 6) so

that the viewfinder tube is roughly

centered within the viewfinder bracket.

ETX-90EC

Fig. 6: The Viewfinder. (1) Front lens cell; (2) Knurled lock-

ring (ETX-90EC) or focus ring (ETX-105EC and ETX-

125EC); (3) Viewfinder eyepiece; (4) Front alignment screws

(one not visible in photo); (5) Viewfinder bracket; (6) Rear

alignment screws (one not visible).

Tip: Do not overtighten the align-

ment screws. When tightening one

screw it may be necessary to loosen

one or both of the two other

alignment screws.

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2. Point the main telescope at some

easy-to-find, well-defined land object,

such as the top of a telephone pole.

Center the object, as precisely as

possible, in the SP 26mm eyepiece's

field of view, then tighten the vertical

and horizontal locks (6 and 9, Fig. 1)

so that the tube cannot move and the

object remains centered (1, Fig. 7).

(before

alignment)

View through the

viewfinder

View through the

telescope eyepiece

3. While looking through the viewfinder,

turn one or more of the three front

viewfinder alignment screws (4, Fig.

6), until the crosshairs of the view-

finder point at precisely the same

position as the view through the

eyepiece of the main telescope

(2, Fig. 7).

(after

alignment)

Check that the viewfinder’s crosshairs

and the main telescope are now pointing

Fig. 7: Aligning the Viewfinder.

at precisely the same object. The viewfinder is now aligned to the main telescope. Unless the alignment

screws are disturbed or the viewfinder jarred, the viewfinder should remain aligned indefinitely.

Tip: If you plan on viewing using higher magnification eyepieces, first locate, center, and focus

the object using a low-power eyepiece (e.g., SP 26mm eyepiece). Then remove the low-power

eyepiece and replace it with a higher-power eyepiece; the object should still be centered in the

field of view. Objects are much easier to locate and center at lower powers; higher powers are

employed simply by changing eyepieces.

OBSERVATION TECHNIQUES

The ETX model telescopes can be used for immediate observation right out of the box. However, becoming

familiar with the fundamentals of a telescope makes subsequent viewing easier and more rewarding.

Choosing an Eyepiece

FOR BEGINNERS

A telescope’s eyepiece magnifies the image

formed by the telescope’s main optics. 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 26mm.

TIPS

Too Much Power?

Can you ever have too much power? If the type of

power you’re referring to is eyepiece magnification,

yes, you can! The most common mistake of the

beginning observer is to “overpower” his or her

telescope by using high magnifications which the

telescope’s aperture and atmospheric conditions

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 300X should

be employed only under the steadiest atmospheric

conditions.

The SP 26mm eyepiece, supplied with your

telescope, gives a wide, comfortable field of

view with high image resolution, while an

optional SP 12.4mm eyepiece, for example,

provides a smaller field of view but higher

magnification when seeing conditions permit.

Low-power eyepieces offer a wide field of

view, bright, high-contrast images, and less

eyestrain during long observing sessions. To

find an object with a telescope, always start

with a low-power eyepiece such as the SP

26mm. When the object is located and

centered in the eyepiece, you may wish to

switch to a higher-power eyepiece to enlarge

the image as much as practical for prevailing

seeing conditions.

Most observers should have three or four additional

eyepieces to achieve the full range of reasonable

magnifications possible with the ETX telescopes.

See OPTIONAL ACCESSORIES, page 20.

Note: Seeing conditions vary widely 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,

back off to a lower-power eyepiece for a

more well-resolved image (Fig. 8a and 7b).

Fig. 8a & b: Jupiter; example of too much magnification.

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Understanding Magnification

The magnification, or power, at which a telescope is operating is determined by two factors: the focal length

of the telescope and the focal length of the eyepiece employed.

Telescope Focal Length is the distance that light travels inside the telescope before reaching a focus. In

the mirror-lens design of the ETX models, however, this focal length is, in effect, compressed by the

telescope’s secondary mirror, so that a long effective focal length is housed in the short ETX optical tube.

For example, the ETX-90EC’s focal length is 1250mm, or about 49”. This means that if the ETX–90EC were

a classical refracting-type of telescope, the optical tube would be more than four feet long instead of the

ETX–90EC's compact 11” tube length.

Eyepiece Focal Length is the distance light travels inside the eyepiece before reaching focus. Focal length

is usually printed on the side of the eyepiece. For instance, the Super Plössl (SP) 26mm eyepiece supplied

with the three ETX models has a focal length of 26mm. “Super Plössl” refers to the optical design of the

eyepiece, a design specifically intended for high-performance telescopes and one which yields a wide,

comfortable field of view with extremely high image resolution.

Technical note to the advanced amateur astronomer: The SP 26mm eyepiece supplied with

the Meade ETX-90EC, ETX-105EC, and ETX-125EC is a special low-profile version of the

standard Meade SP 26mm eyepiece which is about 1/4” (6mm) shorter than the standard

eyepiece. This low-profile SP 26mm is designed to work in harmony with the ultracompact scale

of the ETX models and utilizes the exact same optics as the standard SP 26mm eyepiece. The

SP 26mm low-profile eyepiece is not parfocal with other eyepieces in the SP series (i.e., the

eyepiece requires re-focusing when it is interchanged with other SP eyepieces).

Calculating Magnification: On a telescope, such as the ETX, different eyepiece focal lengths are used to

achieve different magnifications, from low to high. The standard-equipment SP 26mm eyepiece yields 48X

(“48-power”) on the ETX-90EC, 57X on the ETX-105EC, and 73X on the ETX-125EC. A variety of powers

may be obtained with the addition of optional eyepieces as well as the #126 2X Barlow Lens which doubles

the power of an eyepiece (see OPTIONAL ACCESSORIES, page 20).

Telescope Focal Length

____________________

Power =

Eyepiece Focal Length

Example: To obtain the power of an ETX-125EC (which has a 1900mm focal length) using a

SP 26mm eyepiece:

1900mm

________

Power =

= 73X

26mm

Use this formula to calculate the magnification obtained with a given eyepiece:

Most observers should have 3 or 4 eyepieces plus the #126 2X Barlow to achieve the full range of

reasonable magnifications possible with ETX models.

Note:

Throughout this manual,

you will notice the term

"Alt/Az." Alt/Az is

frequently used to refer

to altitude or vertical

and azimuth or

horizontal. Alt/Az is just

one of many methods

used by amateur

astronomers to help

locate stars in the night

sky.

Terrestrial Observing

All three of the ETX models make excellent, high-resolution terrestrial (land) telescopes. When you set the

telescope on its drive base, as shown below in Fig. 9, you may use it for an extremely wide range of

observations. When you look through the eyepiece at a terrestrial object, you will notice that the image is

right-side-up, but reversed left-for-right. Normally, such an image orientation is not bothersome, unless you

are trying to read a distant sign, for example. If the telescope is to be used for extensive terrestrial

observations, a fully correctly oriented image is provided with the #932 45° Erecting Prism (see OPTIONAL

ACCESSORIES, page 20).

Viewing terrestrial objects requires

looking along the Earth's surface through

heat waves. Heat waves often degrade

Azimuth

image quality. Low-power eyepieces, like

the SP 26mm eyepiece, magnify these

heat waves less than higher-power

eyepieces.

Therefore,

low-power

eyepieces provide a steadier, higher-

quality image. If the image in an

eyepiece is fuzzy or ill-defined, reduce to

a lower power. Observing in the early

Fig. 9: Alt/Az mounting moves the telescope in vertical and

horizontal directions.

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morning hours, before the ground has

built up internal heat, results in better

viewing conditions than during the late-

afternoon hours.

Declination

Right Ascension

If you wish to observe a distant land

object, such as a mountain top or a bird,

you can observe by merely pointing the

telescope and looking through the

eyepiece. Set the telescope on a table

top or tripod, loosen the horizontal and

vertical locks (6 and 9, Fig. 1), and turn

the telescope towards the object you

wish to observe. Look into the viewfinder

and move the tube until you find the

object. If the viewfinder is correctly

Fig. 10: Equatorial mounting aligns the telescope with the

celestial sphere (table-top tripod legs optional).

aligned, the object now appears in the eyepiece. Center the object and focus the image using the by turning

the focus knob (8, Fig. 1). Rotate the knob clockwise to focus on distant objects and counterclockwise to

focus on nearby objects.

Astronomical Observing

As an astronomical instrument, your ETX telescope has many optical and electromechanical capabilities. It

is in astronomical applications where the high level of optical performance is readily visible. The range of

observable astronomical objects is, with minor qualification, limited only by the observer’s motivation.

Sidereal Rate

As the Earth rotates beneath the night sky, the stars appear to move from East to West. The speed at which

the stars move across the sky is called the sidereal rate.

You can observe stars and objects in the night sky using the terrestrial viewing method, but note that objects

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

You can counteract the drift by mounting the

telescope to one of the optional tripods in the

polar mode (see POLAR ALIGNMENT

PROCEDURE, page 16). In this mode, the

motor drive in each ETX model is designed to

rotate the telescope at the sidereal rate so that

it automatically follows, that is, "tracks" the

stars. Tracking makes it easier to locate

objects and to keep them centered in the

telescope’s eyepiece. The Electronic

Controller supplied with your telescope assists

with the tracking function.

FOR BEGINNERS

TIPS

•

Try to pick an observing site away from street

and house lights, and car headlights. While

this is not always possible, the darker the site,

the better.

Give your eyes about ten minutes to adjust to

the darkness before observing. Give your eyes

a rest from observing every ten or fifteen

minutes to relieve eyestrain.

Try not to use a standard flashlight. Seasoned

observers use red LED flashlights or tape red

cellophane over their flashlights for setup and

map reading so they don’t have to continually

readjust their eyes to the darkness. Be careful

not to shine bright lights if there are other

observers in the area. Never shine a flashlight

into a telescope while someone is observing!

The Electronic Controller

Functions of the Electronic Controller include:

• Slewing (moving) the telescope's optical

tube assembly to an object

• Turning on the telescope motor drive to

automatically track celestial objects (when

the telescope is polar aligned)

•

Dress warmly. It gets chilly when you’re sitting

for prolonged periods, even on some summer

nights.

• Changing the hemisphere of operation,

when required

Fig. 11: Electronic

Controller.

Practice setting up your equipment during the

day or in a lighted area to become familiar with

it before going to a dark site.

• Changing tracking speed (see APPENDIX A,

page 26)

Slew Speeds

Use your 26mm eyepiece to view terrestrial

objects and wider areas of space, such as

open star clusters. Use your higher power

eyepieces when you wish to view something

up close, such as craters on the Moon or the

rings of Saturn.

The Electronic Controller has four slew

speeds that are directly proportional to the

sidereal rate. Press the Speed key to change

the slew speed. Note each slew speed

corresponds to one of the four LED's of the

Electronic Controller.

•

Know your observing site. If you’re going to try

out an unfamiliar site, check it out in the daylight

for possible obstructions and pitfalls.

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Light 1 (top LED): The fastest speed. Use to move the telescope quickly from one point in the sky to

another.

Light 2: Best for centering an object in the viewfinder.

Light 3: Best for centering an object in the field of a low-to-moderate power eyepiece, such as the standard

SP 26mm.

Light 4: The slowest speed. Use to center an object in the field of view of high-power eyepieces, such as

the optional 6.7mm or 12.4mm.

The four available speeds are:

Light 1 = 1200 x sidereal (300 arc-min/sec or 5°/sec)

Light 2 = 180 x sidereal (45 arc-min/sec or 0.75°/sec)

Light 3 =

Light 4 =

32 x sidereal (8 arc-min/sec or 0.13°/sec)

8 x sidereal (2 arc-min/sec or 0.034°/sec)

The two slowest speeds (8x and 32x sidereal) can be used for pushbutton (manual) tracking of astronomical

objects while observing through the eyepiece.

Modes of Operation

The Electronic Controller can be set to operate in either of two primary modes: the Alt/Az mode (used when

the telescope is operated in the altazimuth configuration; see below) and the polar mode (used when the

telescope is polar- (or equatorial) aligned; see page 16).

• Choose the Alt/Az (altitude-azimuth, or vertical-horizontal) mode for all terrestrial operations of the

telescope. In the Alt/Az mode, use the Arrow keys to slew the telescope to terrestrial or astronomical

objects and, once you locate them, follow these objects if they move. However, in this mode astronomical

tracking is not automatic and requires continuous pushes of the Arrow keys. The Electronic Controller is

factory pre-set to the Alt/Az mode.

• Choose the polar mode when the telescope is equipped with either the optional #880 (ETX–90EC) or #881

(ETX-105EC or ETX-125EC) Table Tripod, or #883 Deluxe Field Tripod, for extensive astronomical

observations. In this mode use the Arrow keys to slew the telescope to objects. In addition, the telescope’s

internal motor drive is turned on, enabling the telescope to automatically track celestial objects.

You can configure the two screws on the bottom rear of the Electronic Controller handbox to change the

default mode of the Electronic Controller to Alt/Az or polar. When in polar mode, you may also set the

alignment to the hemisphere in which you are located (not necessary in the Alt-Az mode).

Caution: Mode screws A and B are the outer screws in the recess directly under the letters A and

B on the rear of the Electronic Controller. Do not remove either of the inner two screws in the

recess.

• Remove mode screw A (1, Fig. 12) to make the Northern hemisphere polar mode the automatic default

of the Electronic Controller when power is applied (i.e., the motor drive is activated for operation in the

Earth’s Northern Hemisphere).

• Remove mode screw B (2, Fig. 12) to make the Southern Hemisphere polar mode the automatic default

of the Electronic Controller when power is applied (i.e., the motor drive is activated for operation in the

Earth’s Southern Hemisphere ).

• Leave both the A and B screws in place (or remove both screws) to keep the telescope in the original

factory default Alt/Az mode.

Note: Removing either A or B screw affects only the telescope’s default mode; you may still make

mode changes when desired using the MODE key (see, APPENDIX A, page 26).

Telescope Mountings

A mount allows a telescope to move on

Meade Instruments Corporation

its axes. The two basic types of

mounting are Altazimuth (Alt/Az) and

Polar (Equatorial).

35-4702-00

Tested to comply

with FCC Standards

FOR HOME OR OFFICE USE

Alt/Az Mode

Altazimuth (Alt/Az) mounting permits

movement of the telescope tube in

vertical (altitude) and horizontal

(azimuth) directions. The ETX models

incorporate an altazimuth mount (as

shown in Fig. 9), ideal for terrestrial

Fig. 12: Mode screws on rear of Electronic Controller.

(1) Mode screw A; (2) Mode screw B.

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applications and for casual astronomical observation. The telescope may be placed on a rigid tabletop or

on the optional Meade #883 Deluxe Field Tripod (see OPTIONAL ACCESSORIES, page 20) to provide a

secure, variable-height, altazimuth observing platform. To manually track objects with the telescope in the

altazimuth configuration, press the Arrow keys of the Electronic Controller as necessary to keep an object

centered.

Note: Automatic tracking of objects is not possible with the ETX-90 EC, ETX-105EC and the ETX-

125EC in the Alt/Az mounting.

With the Electronic Controller in the factory pre-set “Alt/Az” (vertical-horizontal) mode, the Electronic

Controller Arrow keys permit pushbutton movements (slewing) of the telescope.

To move the telescope using the Electronic Controller:

1. Set the telescope on a level and stable surface, or mount to the Meade #883 Deluxe Field Tripod (see

OPTIONAL ACCESSORIES, page 20).

2. Insert a low-power eyepiece (e.g., SP 26mm) into the eyepiece holder (4, Fig. 1) and tighten the

eyepiece thumbscrew (3, Fig. 1).

3. Tighten the vertical and horizontal locks (6 and 9, Fig. 1), if necessary.

4. Verify that the power switch (10A, Fig. 1) on the telescope’s Computer Control panel is OFF.

5. Plug in the Electronic Controller coil cord (4, Fig. 3) to the HBX port (10C, Fig. 1) on the Computer

Control panel.

6. Flip the power switch to ON. The power indicator (10E, Fig. 1) on the Computer Control panel lights

and all four speed indicators (2, Fig. 3) blink rapidly.

7. Press any key on the Electronic Controller and the telescope slews momentarily in the vertical and

horizontal directions to test the motors.

8. When the test is complete, light 1 remains

FOR BEGINNERS

on; lights 2, 3, and 4 turn off.

TIPS

9. Use the four Arrow keys (1, Fig. 3) to slew

the telescope to the desired object. To

change the slew speed, press the SPEED

key.

Surf the Web

One of the most exciting resources for astronomy is

the Internet. The Internet is full of websites with

new images, discoveries, and the latest

astronomical information. For example, when

comet Hale-Bopp made its approach to our Sun in

1998, astronomers around the world posted new

photos daily.

10. Fine-adjust the position of the object with

the Electronic Controller Arrow keys so

that it is centered in the viewfinder. The

object is now ready to be viewed through

the telescope’s eyepiece.

You can find websites for virtually any topic relating

to astronomy on the internet. Try the following key

word searches: NASA, Hubble, HST, astronomy,

Messier, satellite, nebula, black hole, variable stars,

extrasolar, Chandra, gamma burster, etc.

Polar Mode

If you are to use your ETX-90EC, ETX-105EC,

or ETX-125EC telescope for extensive

astronomical applications, it is recommended

you use Polar or Equatorial mounting. By

tilting one of the telescope’s mechanical axes

(see Fig. 10) to point at the celestial pole (i.e.,

by pointing one axis of the telescope to the

North Star, Polaris), you may follow (track)

astronomical objects through the sky.

Check out Meade’s website for the latest product

and technical information. You can download the

latest software revisions, links to other

astronomical sites, coordinates of celestial objects

and the latest satellite tracking information for the

optional #497 Autostar handset. See page 20 for

more information. You’ll find our website at:

http://www.meade.com/

The telescope's optical tube turns on only one

axis of the telescope instead of simultaneously

turning on two axes, as required of the

Altazimuth mount. An Equatorial mount which

has one of its axes (the polar axis) pointing to the

celestial pole is said to be polar aligned. The ETX

models can be polar aligned either by using the

optional #883 Deluxe Field Tripod or the table

tripod specific to your model of ETX telescope

(see OPTIONAL ACCESSORIES, page 20).

Here are some other sites you might find useful:

• Sky & Telescope:

http://www.skypub.com/

• Astronomy:

http://www.astronomy.com/astro/

• The Starfield:

http://users.nac.net/gburke/

• Astronomy Picture of the Day:

http://antwrp.gsfc.nasa.goc/apod/

• Heavens Above (satellite observing information):

http://www.heavens-above.com/

• Photographic Atlas of the Moon:

http://www.lpi.ursa.edu/research/lunar_orbiter

• Hubble Space Telescope Public Pictures

With the ETX polar aligned, the telescope’s

internal motor drive may be activated (see

APPENDIX A, page 26) to enable fully automatic

hands-off tracking of celestial objects. In this

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configuration the observer does not need to press the Arrow keys of the Electronic Controller in order to

track celestial objects. However, the Arrow keys of the Electronic Controller are useful in this configuration

to enable the centering of objects within the telescopic field or, for example, to move the telescope over the

surface of the Moon or through a large star field.

Celestial Coordinates

Before polar aligning your ETX model, it is helpful to understand how to locate celestial objects as they

move across the sky.

A celestial coordinate system was created that maps an imaginary sphere surrounding the Earth upon which

all stars appear to be placed. This mapping system is similar to the system of latitude and longitude on Earth

surface maps.

In mapping the surface of the Earth, lines of longitude are drawn between the North and South Poles and

lines of latitude are drawn in an East-West direction, parallel to the Earth’s equator. Similarly, imaginary lines

have been drawn to form a latitude and longitude grid for the celestial sphere. These lines are known as

Right Ascension and Declination.

The celestial map also contains two poles and an equator just like a map of the Earth. The poles of this

coordinate system are defined as those two points where the Earth’s north and south poles (i.e., the Earth's

axis), if extended to infinity, would cross the celestial sphere. Thus, the North Celestial Pole (1, Fig. 13) is

that point in the sky where an extension of the North Pole intersects the celestial sphere. The North Star,

Polaris is located very near the North Celestial Pole (1, Fig. 13). The celestial equator (2, Fig. 13) is a

projection of the Earth’s equator onto the celestial sphere.

So just as an object's position on the Earth’s surface can be located by its latitude and longitude, celestial

objects may also be located using Right Ascension and Declination. For example, you could locate Los

Angeles, California, by its latitude (+34°) and longitude (118°). Similarly, you could locate the Ring Nebula

(M57) by its Right Ascension (18hr) and its Declination (+33°).

• Right Ascension (R.A.): This celestial version of longitude is measured in units of hours (hr), minutes

(min), and seconds (sec) on a 24-hour "clock" (similar to how Earth's time zones are determined by

longitude lines). The "zero" line was arbitrarily chosen to pass through the constellation Pegasus — a sort

of cosmic Greenwich meridian. R.A. coordinates range from 0hr 0min 0sec to 23hr 59min 59sec. There

are 24 primary lines of R.A., located at 15-degree intervals along the celestial equator. Objects located

further and further East of the zero R.A. grid line (0hr 0min 0sec) carry higher R.A. coordinates.

• Declination (Dec.): This celestial version of latitude is measured in degrees, arc-minutes, and arc-

seconds (e.g., 15° 27' 33"). Dec. locations north of the celestial equator are indicated with a plus (+) sign

(e.g., the Dec. of the North celestial pole is +90°). Dec. locations south of the celestial equator are

indicated with a minus (–) sign (e.g., the Dec. of the South celestial pole is –90°). Any point on the celestial

equator (such as the the constellations of Orion, Virgo, and Aquarius) is said to have a Declination of zero,

shown as 0° 0' 0."

Locating the Celestial Pole

To get basic bearings at an observing location, take note of where the sun rises (East) and sets (West) each

day. After the site is dark, face North by pointing your left shoulder toward the direction where the sun set.

To point at the pole, find Polaris by using the Big Dipper as a guide (Fig. 14).

Polar Alignment Procedure

As the Earth rotates once on its axis every

24 hours, astronomical objects appear to

move across the sky in an arc. This

apparent motion (see SIDEREAL RATE,

page 13) is not obvious to the unaided eye,

but viewed through a telescope such as the

ETX-90EC, ETX-105EC, or ETX-125EC,

this motion is rapid indeed. If the motor

drive has not been engaged, objects

centered in the telescope’s eyepiece move

entirely out of the field of view in 30 to 160

seconds, depending on the magnification

+90° Dec.

North Celestial Pole

(Vicinity of Polaris)

Star

Earth’s

Rotation

Celestial Equator

Right Ascension

0° Dec.

employed.

For

easy

tracking

astronomical objects your ETX telescope

-90° Dec.

South Celestial Pole

should be polar aligned.

Fig. 13: The Celestial Sphere.

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There are two mounting methods available to polar

align the telescope depending on whether you use the

optional #883 Deluxe Field Tripod or a table tripod

(specific to your model of ETX telescope).

22°

Little Dipper

33°

Polaris

To polar align using the #883 Deluxe Field Tripod (Fig.

17), follow the instructions provided with the tripod. To

polar align using the #880 (ETX-90EC) or #881 Table

Tripod (ETX-105EC or ETX–125EC, Fig. 16), use the

following procedure.

34°

23°

Big Dipper

Cassiopeia

Fig. 14: Locating Polaris.

35°

1. Make sure the viewfinder is aligned with your ETX

telescope (see ALIGNING THE VIEWFINDER, page

10).

24°

36°

2. Remove the two hole covers (12, Fig. 1) from the side of the drive base and thread the two identical

fixed legs (4, Fig. 16) into these holes to a firm feel only.

25°

37°

3. Determine the latitude of the observing location from a road map, atlas, or the Latitude Chart for Major

Cities of the World, page 27; determining the latitude within about one degree is sufficient.

26°

4. Each table tripod is equipped with two adjustable tripod legs, only one of which will be used: The

standard tripod leg is used at observing latitudes as shown in step 5 and has a dual latitude label

attached (Fig. 15). The high-latitude tripod leg is shorter and is used at higher observing latitudes.

5. Locate the two mounting holes on the bottom of the telescope drive base. Mount the appropriate

adjustable tripod leg to the drive base using the following latitudes:

38°

39°

27°

Standard Tripod Leg (ETX-90EC)

40°

32.5° to 48.5° uses high-latitude hole (2, Fig. 16). 22° to 35.5° uses alternate hole (3, Fig. 16).

High-Latitude Tripod Leg (ETX-90EC)

28°

41°

42°

43°

56° to 66° uses high-latitude hole. 44° to 55° uses alternate hole.

Standard Tripod Leg (ETX-105EC, ETX-125EC)

29°

33.5° to 49.5° uses high-latitude hole. 23.25° to 36.5° uses alternate hole.

High-Latitude Tripod Leg (ETX-105EC, ETX-125EC)

30°

56.6° to 67° uses high-latitude hole. 44.5° to 56.5° uses alternate hole.

Thread the appropriate leg into the required hole to a firm feel only. Set aside the tripod leg that is not to

be used.

31°

44°

45°

46°

6. A small thumbscrew (6, Fig. 16) is attached to both the standard and high-latitude tripod legs. Loosening

the thumbscrew allows the outer section of the leg to slide over the inner section, so that the leg can be

extended. If using the standard tripod leg, extend the leg so that the center of the thumbscrew head

aligns with the latitude of the observing location on the scale. Retighten the thumbscrew to a firm feel. (If

using the high-latitude tripod leg, complete the adjustment of the leg extension in step 9.)

32°

33°

34°

47°

Example: The latitude of New York

City is 41°. The tripod leg should be

extended so that the center of the

thumbscrew is set next to the 41°

reading on the scale.

48°

35°

Fig. 15:

Example of

Standard Tripod

Leg Latitude

Scales.

Note: With the standard tripod leg

threaded into the appropriate hole in

the drive base, the latitude scale may

be at an inconvenient position for

reading (e.g., the scale faces the

drive base). This situation can be

remedied by unthreading the leg,

removing the thumbscrew, rotating

the inner leg 180°, then reinserting

the thumbscrew. The scale will now

be readable when threaded back into

the telescope base.

Dec. at 90°

Fig. 16: Example of Polar Alignment Using the #880 Table

Tripod and ETX-90EC. (1) Standard tripod leg with latitude

scale; (2) High-latitude hole; (3) Alternate hole; (4) Fixed tripod

legs; (5) Declination pointer; (6) Thumbscrew;

7. Loosen the vertical and horizontal

locks (6 and 9, Fig. 1) and rotate the

telescope so that it is oriented as

shown in Fig. 16. Tighten the vertical

(7) R.A. scale pointer; (8) #1422 low-latitude balance weight

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and horizontal locks. In this

orientation the telescope’s optical

tube is lined up parallel to the

tripod’s adjustable leg.

CAUTION!

When using the #880 Table

Tripod with the ETX-90EC,

the optional #1422 Low-

Latitude Balance Weight is

recommended if the

telescope is to be polar

aligned below 30°, or if

heavy accessories are

attached to the eyepiece-

end of the telescope. The

low-latitude balance

weight is recommended

for the ETX-105EC or ETX-

125EC at all observing

latitudes and is included

as standard equipment

with the #881 Table Tripod.

ALT/AZ:

Tripod head

locked at 90°

8. Note the line and arrow extending

from the telescope tube in Fig. 16.

This line defines the telescope’s

polar axis. Lift the entire telescope,

including tripod, and place the

POLAR:

Tripod head

locked at

observer’s

latitude

telescope on

firm and level

surface so that this axis is pointing

due North (i.e., if the location of

Polaris, the North Star, is known,

then point the telescope directly at

Polaris).

9. If using the high-latitude tripod leg in

the Northern hemisphere, extend

the leg until the telescope’s polar

axis points to Polaris, or due North,

an alignment obtained by sighting

Fig. 17: Examples of Alt/Az and polar mounting of an

ETX-90EC to the optional #883 Deluxe Field Tripod.

along the telescope tube with the telescope oriented as shown in Fig. 16.

Note: Observers located in the earth’s Southern Hemisphere must point the telescope’s polar

axis due South.

10.With the telescope now polar-aligned, the table tripod should not be moved, or else polar alignment will

be lost. Motions of the telescope (e.g., to locate and/or track objects) can be affected only by (a)

loosening the locks (6 and 9, Fig. 1), which permits the optical tube to be moved freely within the

telescope mounting, or (b) more generally, with the locks in their “locked” positions, by using the Arrow

keys of the Electronic Controller.

Note: For almost all astronomical observing requirements, approximate settings of the

telescope’s polar axis are acceptable. Do not allow undue attention to precise polar alignment of

the telescope to interfere with your enjoyment of the instrument. In those unusual cases where

more precise polar alignment is desirable, refer to APPENDIX C, page 28.

PHOTOGRAPHY

Photography through your ETX model requires the addition of the optional #64 T-Adapter (see OPTIONAL

ACCESSORIES, page 20). With the #64 T-Adapter attached to the telescope (Fig. 18), through-the-telescope

photography is possible with any 35mm camera body with a removable lens. In this way the telescope

effectively becomes the lens of the camera.

For through-the-telescope photography, turn the flip-mirror control (5, Fig. 18) to the “down” position,

allowing light to pass straight through the telescope and out the photo port (15, Fig. 1). With the flip-mirror

control in the “down” position and the photo port’s dust cover removed, you can see the front lens of the

telescope when you look through the photo port. The #64 T-Adapter threads onto the photo port, followed

by a T-mount for the particular brand of 35mm camera being used, followed by the camera body (with the

camera lens removed).

The #64 T-Adapter consists of two sections (1 and 2, Fig. 18), which are threaded together in shipment.

You may use either of the following photographic mounting formats to couple the camera body to the

telescope’s photo port thread.

• Format 1: Camera Body + T-Mount + Section (1) of the #64 T-Adapter (7, Fig. 18).

ETX-90EC

ETX-105EC

ETX-125EC

1250mm at f/13.8

1640mm at f/15.6

1900mm at f/15

Format 1 utilizes only the short section of the #64 T-Adapter to permit close-coupling of a camera body to

the telescope. In this format vignetting will occur: the photographic image will appear on film with a slight

darkening at the corners of the 35mm frame (see Fig. 19).

• Format 2: Camera Body + T-Mount + Sections (1) and (2) of the #64 T-Adapter (see Fig. 18).

ETX-90EC

ETX-105EC

ETX-125EC

1450mm at f/16

1830mm at f/17.4

2310mm at f/18

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Format 2 utilizes both sections of the

#64 T-Adapter threaded together to

form a rigid unit. In this configuration

there is no field vignetting: images are

illuminated to the edges of a standard

35mm frame (see Fig. 20).

To frame an object in the viewfinder of

the 35mm camera body, slightly

loosen the knurled attachment ring (3,

Fig. 18), which threads the #64 T-

Adapter to the telescope’s photo port;

rotate the camera body to achieve

proper framing of the object; then re-

tighten the knurled ring.

Fig. 18: Example of photography through the ETX using the

#64 T-Adapter: (1) Short section of #64 T-Adapter;

(2) Extension section of #64 T-Adapter; (3) Knurled attachment

ring; (4) T-mount; (5) Flip-mirror control in “down” position; (6)

Photography through a long lens, such

as the ETX, requires special technique

for good results. The photographer

should expect to use a roll or two of 35mm camera body; (7) Format 1.

film in acquiring this technique. Long-

lens photography has its own rewards, however, which short-focus lenses cannot duplicate.

A Few Tips on Photography

1. Use the optional table tripod specific to your model of ETX, or the #883 Deluxe Field Tripod as a platform

for the telescope. At effective focal lengths of 1250mm to 1450mm (ETX-90EC), 1640mm to 1830mm

(ETX-105EC), or 1900mm to 2310mm (ETX–125EC), even small external vibrations can easily ruin an

otherwise good photo.

CAUTION: With the #64 T-Adapter and a camera body mounted to the ETX photo port, the

telescope can be rotated vertically only 45°. Moving past this point may damage the telescope

and camera.

2. Use a cable-operated shutter release. Touching the camera body to operate the shutter will almost

certainly introduce undesirable vibrations.

Fig. 19: Example of a

format 1 photo.

3. Focus the image with extreme care. While observing the subject through the camera’s reflex viewfinder,

turn the ETX's focus knob (8, Fig. 1) to achieve the sharpest possible focus. Note that some 35mm

cameras may have an optional focusing screen (available from the manufacturer) for use with a long

telephoto lens. This screen provides a brighter and clearer image to focus and is highly recommended.

4. Correct shutter speeds vary widely, depending on lighting conditions and film used. Trial-and-error is the

best way to determine proper shutter speed in any given application.

Note: The camera used with an ETX model may have an exposure meter that is still active when

the standard lens is removed and the body is connected to the telescope with the T-mount. If used

for terrestrial photography, the camera meter should be acceptable. If used for astrophotography,

the meter probably will not provide good results since camera meters are not made to

compensate for a dark sky.

Fig. 20: Example of a

format 2 photo.

5. Terrestrial photography through an ETX model is sensitive to heat waves rising from the Earth’s surface.

Long distance photography is best accomplished in the early morning hours before the earth has had

time to build up heat.

6. Photography of the Moon and planets through an ETX model can be especially gratifying, but points

1 through 4 should be particularly noted in this case. Lunar or planetary photography requires that the

telescope be polar aligned (see POLAR ALIGNMENT PROCEDURE, page 16), and that the telescope’s

motor drive be in operation (see APPENDIX A, page 26).

Note: Long-exposure photography of deep-sky objects is not practical with an ETX model, since

this type of photography requires special electronic and optical guiding devices not available for

this telescope.

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OPTIONAL ACCESSORIES

A wide assortment of professional Meade accessories are available for the for ETX telescopes. Meade

accessories greatly extend many important applications to the telescope, from low-power, wide-field

terrestrial viewing to high-power lunar and planetary observing. The premium quality of these accessories

is well-suited to the quality of the instrument itself.

Meade telescopes and accessories, including optional accessories for ETX telescopes, are available at

more than 3,000 dealer locations in the U.S. and Canada and through Meade international distributors

worldwide. Once you have identified the accessories you wish to order, contact your local Meade authorized

dealer. To find a dealer near you call (949) 451-1450 or visit the Meade website at www.meade.com.

™

#497 Autostar Computer Controller: One of the most important advances in telescope control in the

past 25 years, the Meade #497 Autostar Computer Controller (Fig. 21) turns your ETX model into an

automatic celestial object locating system. Just plug Autostar into the telescope’s HBX port in place of the

standard-equipment Electronic Controller, do a quick telescope alignment, and you are ready to observe

any object in the Autostar’s 14,000-object database.

Best of all, the Meade Autostar is easy to use. Even the most novice observer will locate dozens of

fascinating celestial objects the very first night out — from commonly observed objects, such as the rings of

Saturn, the satellites of Jupiter, and the Orion Nebula (M42), to more difficult objects, such as the Ring

Nebula (M57) in Lyra, the Spiral Galaxy (M33) in Triangulum, and the Sombrero Galaxy (M104) in Virgo; to

very obscure objects near the telescope’s threshold of visibility, such as spiral galaxy NGC 3310 in Ursa

Major.

Fig. 21: #497

Autostar Computer

Controller.

Any of Autostar’s database objects can be called up and entered on the hand controller display in seconds.

The observer then simply presses the GO TO pushbutton and watches as the telescope automatically slews

to the object and places it in the field of view. Autostar brings into easy access objects that were previously

unreachable for all but the most dedicated of amateur astronomers.

AstroFinder Software/#505 Cable Connector Kit: With Meade AstroFinder software (Fig. 22) loaded

into your PC, Autostar-equipped ETX–90EC, ETX-105EC, and ETX-125EC telescopes may be remotely

controlled from the PC display. The #505 Cable Connector Set, permitting connection of ETX, Autostar,

and PC, is included with each AstroFinder package.

Fig. 22: AstroFinder

software.

Eyepieces: For higher and lower magnifications, Meade Super Plössl (SP) and Super Wide Angle (SWA)

eyepieces (Fig. 23), as well as the Series 4000 8mm to 24mm Zoom eyepiece, yield high-resolution imaging

with all ETX telescope models. A useful selection includes the SP 9.7mm, SP 12.4mm, and SWA 18mm.

Under good seeing conditions, Meade Ultra Wide Angle 4.7mm and 6.7mm eyepieces present the widest

obtainable fields of view at high powers and are well suited for observing the Moon and planets. Alternative

optional eyepieces may be chosen from the Meade Series 3000 Plössl eyepieces. Powers obtained with

each eyepiece are shown in the following table.

ETX-90EC

ETX-105EC

ETX-125EC

Eyepiece

Power 2x Barlow

Power 2x Barlow Power 2x Barlow

SP 6.4mm

SP 9.7mm

SP 12.4mm

SP 15mm

SP 20mm

SP 26mm *

SP 32mm

SP 40mm

195X

129X

101X

83X

63X

48X

390X

258X

202X

166X

126X

96X

230

152

119

459

303

237

196

147

113

297X

196X

153X

127X

95X

73X

59X

48X

594X**

392X

306X

253X

190X

146X

119X

96X

Fig. 23: Optional

Eyepieces yield higher

and lower magnifying

powers.

39X

31X

78X

62X

SWA 13.8mm

SWA 18mm

SWA 24.5mm

91X

69X

51X

182X

138X

102X

107

213

163

120

138X

106X

78X

275X

211X

155X

UWA 4.7mm

UWA 6.7mm

266X

187X

N/A

374X **

313

219

N/A

439**

404X

284X

N/A

567X**

Included as standard-equipment with the ETX models.

** Use these eyepieces only under extremely steady atmospheric conditions.

Fig. 24: Use the

#126 2x Barlow Lens

to double the

magnification of the

eyepiece employed.

#126 2x Barlow Lens: An amplifying lens, the multi-coated #126 2x Barlow (Fig. 24) doubles the power of

all eyepieces with which it is used. Insert the #126 into the telescope’s eyepiece holder first, followed by an

eyepiece. Example: By itself, the SP 26mm eyepiece yields a power of 73X with the ETX-125EC; when

used with the #126 2x Barlow Lens, this eyepiece yields 146X.

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#825 8 x 25mm Right-AngleViewfinder: Included as standard-equipment on ETX-105EC and ETX-125EC

models, the 8x25mm Right-Angle Viewfinder (Fig. 25) permits a comfortable 90° viewing position with

90mm ETX models as well. The #825 fits into the same bracket as the 8x21mm viewfinder supplied with

ETX-90EC telescopes. The viewfinder’s wide-angle 7.5° actual field facilitates object location. Precise

focusing of the image is accomplished with a helicoid mechanism.

#64 T-Adapter: The basic means of photography through any ETX Astro telescope, the #64 T-Adapter

threads to the rear cell of the telescope, followed by a T-Mount appropriate to the user’s brand of 35mm

camera. In this way, the camera body is rigidly coupled to the telescope's optical system, which in effect

becomes the camera's lens (see PHOTOGRAPHY, page 18).

Fig. 25: #825 Right-

Angle Viewfinder.

#932 45° Erecting Prism: All ETX models include an internal optically-flat mirror to reflect light to the

telescope’s 90° astronomical observing position. In this position the telescope’s image is upright, but

reversed. For terrestrial observing with an ETX model, the #932 Erecting Prism (Fig. 26) results in a fully

correctly oriented image and a convenient 45° observing angle.

#774 Hard Carrying Case (for the ETX-90EC), #776 Hard Carrying Case (for the ETX-105EC), and #775

Hard Carrying Case (for the ETX-125EC): For secure portability of ETX Astro Telescope models in the field,

Meade hard carrying cases (Fig. 27) are fully lined with fitted foam inserts. They accept the complete ETX

Astro Telescope plus optional accessories.

Fig. 26: The #932 45°

Erecting Prism.

#765 Soft Carry Bag: The Meade soft-padded carry bag (Fig. 28) is well suited to travel with the ETX-90EC

Astro Telescope. Each carry bag includes a shoulder strap and permits ready transport of the complete

telescope, including accessories.

Power Adapters and Cords: In addition to their internal battery packs, ETX-90EC, ETX-105EC, and ETX-

125EC telescopes may be powered from standard 115vAC home electricity with the #541 AC Adapter. The

#541 plugs into any standard home outlet and includes a 25 ft. cord connecting to the telescope’s control

panel. Input voltage to the telescope is 12vDC. Alternately, an ETX telescope may be powered in the field

from an automobile cigarette lighter plug by using the #607 Power Cord, a 25-ft. cord that plugs into the

telescope’s control panel and supplies 12vDC directly from the car battery.

#1244 Electric Focuser (for the ETX-90EC and ETX-105EC) and #1247 Electric Focuser (ETX-125EC):

Meade-engineered for smooth, rapid focusing with any ETX model, each electric focuser (Fig. 29) includes

coarse and micro-fine speeds. The standard-equipment hand controller accepts one (user-supplied) 9-volt

battery and focuses the ETX telescope. On the ETX models, the focuser plugs into, and is powered by, the

telescope’s control panel, with operation effected through either the Electronic Controller or the optional

#497 Autostar Computer Controller.

#880 Table Tripod (for ETX-90EC) and #881 Table Tripod (for ETX-105EC and the ETX-125EC): ETX-

90EC, ETX-105EC, and ETX-125EC models permit pushbutton tracking of astronomical objects from their

standard-equipment Electronic Controllers. For fully automatic tracking, a table tripod (Fig. 16), or the #883

Deluxe Field Tripod, may be added allowing for polar alignment of the telescope.

Each table tripod includes two fixed legs and two variable-length legs inscribed with a range of latitude

settings for quick polar alignment. At observing latitudes below about 25°, the optional #1422 Low-Latitude

Balance Weight (8, Fig. 16) is recommended for ETX-90 Astro Telescope models; the low-latitude balance

weight is included with the table tripod for the ETX-105EC and the ETX-125EC Astro Telescopes.

Fig. 30a: The #883

Deluxe Field Tripod

shown with an ETX-

90EC Astro Telescope,

set up in the Alt/Az

configuration (tripod

head locked at 90°), for

terrestrial applications.

#883 Deluxe Field Tripod: Provides a rigid mounting platform for the ETX-90EC, ETX-105EC, and ETX-

125EC Astro Telescope models. The #883 tripod includes micrometric controls for precise equatorial

alignment of the telescope at any observing latitude from 20° to 90°. The ETX telescope may be mounted

in the altazimuth orientation (Fig. 30a) for terrestrial viewing or in the equatorial (or polar) mode (Fig. 30b)

for automatic tracking of astronomical objects.

#887 Advanced Field Tripod for the ETX-105EC or ETX-125EC: For extra stability in sensitive

applications of the ETX-105EC or the ETX-125EC even at the highest magnifications, the fixed height #887

Tripod permits either altazimuth or equatorial orientation of the telescope for astronomical or terrestrial

observing. The #887 includes an equatorial wedge for polar alignment. The tripod's 2"-diameter steel legs

collapse for easy transport in the field.

Fig. 30b: The #883

Deluxe Field Tripod

shown with tripod head

tilted for polar alignment.

Fig. 27: #774 Hard

Carrying Case shown with

an ETX-90EC.

Fig. 28: The #765 Soft

Carry Bag for the ETX-

90EC.

Fig. 29: #1244 Electric

Focuser.

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GENERAL MAINTENANCE

Your ETX model telescope is a precision optical instruments designed to yield a lifetime of rewarding

observations. Given the care and respect due any precision instrument, the telescope will rarely require

factory servicing or maintenance. Use the following guidelines:

1. Avoid cleaning the telescope’s optics: a little dust on the front surface of the telescope’s correcting lens

causes virtually no degradation of image quality and should not be considered reason to clean the lens.

2. When absolutely necessary, remove dust from the front lens with gentle strokes of a camel-hair brush or

blow it off with an ear syringe (available at any pharmacy). Do not use a commercial photographic lens

cleaner.

3. You may remove organic materials (e.g., fingerprints) from the front lens with a solution of 3 parts distilled

water to 1 part isopropyl alcohol. A single drop of biodegradable dishwashing soap may be added per

pint of solution. Use soft, white facial tissues and make short, gentle strokes. Change tissues often.

CAUTION: Do not use scented, colored, or lotioned tissues or damage could result to the optics.

4. In the very rare situation where cleaning the inside surface of the corrector lens becomes necessary,

unthread the lens cell located at the front of the main tube. The entire correcting lens and secondary

mirror system are mounted in this cell. You may use the lens-cleaner solution described in step 3 to clean

the inside surface of the lens.

CAUTION: Do not touch the aluminized circular surface of the secondary mirror with a finger, a

tissue, or any other object. This will almost certainly scratch the mirror surface.

Note: When cleaning the inside surface of the correcting lens, leave the lens mounted in its metal cell

throughout the process. Do not remove the lens from its metal housing or optical alignment of the lens will

be lost, necessitating a return of the telescope to the Meade factory.

5. If your ETX model is used outdoors on a humid night, telescope surfaces may accumulate water

condensation. While such condensation does not normally cause any damage to the telescope, it is

recommended that the entire telescope be wiped down with a dry cloth before being packed away. Do

not, however, wipe any of the optical surfaces. Rather, simply allow the telescope to sit for some time in

warm indoor air, so that the wet optical surfaces can dry unattended. In addition, the dust cap should not

be placed back on to the optical tube until the telescope is thoroughly dry.

6. If your ETX model is not to be used for an extended period, perhaps for one month or more, it is advisable

to remove the eight AA-size batteries from inside the drive base. Batteries left installed for prolonged

periods may leak, causing damage to the telescope’s electronic circuitry (see ASSEMBLY INSTRUCTIONS,

page 9).

7. The super-gloss anodized finish of any ETX model’s deep-violet optical tube fades if left in direct sunlight

for prolonged periods.

8. Do not leave your ETX model outdoors on a warm day or inside a sealed car for an extended period of

time; excessive ambient temperatures can damage the telescope’s internal lubrication and electronic

circuitry.

9. A set of two (English-format) hex wrenches is provided with ETX models. These wrenches are used as

follows:

• Small wrench (.05”): Use the small wrench to tighten the set-screws of any knobs that may loosen (e.g.,

the focus knob or flip-mirror control knob).

• Medium wrench (1/16”): This wrench is used to detach the viewfinder bracket from the telescope’s rear

cell.

Storage and Transport

When the telescope is not in use, store it in a cool, dry place. Do not expose the instrument to excessive

heat or moisture. It is best to store the telescope in its original box with the vertical and horizontal locks (6

and 9, Fig. 1) in the unlocked positions. If shipping the telescope, use the original box and packing material

to protect the telescope during shipment.

When transporting the telescope, take care not to bump or drop the instrument; this type of abuse can

damage the optical tube and/or the objective lens, and knock the optics out of alignment. It is highly

recommended to use an optional carry case to transport the telescope (see OPTIONAL ACCESSORIES,

page 21).

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Inspecting the Optics

A Note About the “Flashlight Test:" If a flashlight or other high-intensity light source is pointed down the main

telescope tube, the view (depending upon the observer’s line of sight and the angle of the light) may reveal

what appear to be scratches, dark or bright spots, or uneven coatings, giving the appearance of poor quality

optics. These effects are only seen when a high intensity light is transmitted through lenses or reflected off

the mirrors, and can be seen on any high-quality optical system, including giant research telescopes.

The optical quality of a telescope cannot be judged by the “flashlight” test; the true test of optical quality can

only be conducted through careful star testing.

Troubleshooting

The following suggestions may be helpful with operation of the ETX-90EC, ETX-105EC, and ETX-125EC.

The power indicator light on the telescope does not come on or there is no response

when pressing the Electronic Controller Arrow keys:

• Verify that the Computer Control panel power switch (10A, Fig. 1) is in the ON position.

• Verify that the Electronic Controller cord (4, Fig. 3) is firmly connected to the HBX port (10C, Fig. 1).

• If using internal power (batteries), verify that the batteries are installed correctly and that they have

sufficient charge (see ASSEMBLY INSTRUCTIONS, page 9).

Note: If the batteries are getting low on charge, there will be a marked difference in the slew

speed. The speed indicator lights may also flash and the speed may change. If any of these

symptoms occurs, turn the power off and replace the batteries.

• If using an external power source, verify that it is properly connected between the 12-volt connector

(10D, Fig. 1) and either a wall plug (AC source) or a car cigarette lighter (DC source).

• If the Electronic Controller does not respond to commands, move the power switch to OFF and then back

to ON.

• If the telescope does not slew after power is applied or if the motor quits or stalls, verify that there are no

physical obstructions that would impede telescope movement.

• If all physical obstacles are removed and the telescope still does not move properly, turn off the power

and unplug the Electronic Controller. Plug the Electronic Controller back in and turn the power back on.

Unable to see an image through the eyepiece:

• Confirm that the lens cover has been removed from the telescope.

• Confirm that the flip-mirror control (14, Fig. 1) is in the “up” position if using the eyepiece holder (4, Fig.

1) so that light is directed to the eyepiece (1, Fig. 1). Confirm that the flip-mirror control is in the “down”

position if using the #932 Erecting Prism or doing photography with an ETX model (see TELESCOPE

CONTROLS, page 6 and PHOTOGRAPHY, page 18).

Object appears in the viewfinder but not in the eyepiece:

• The viewfinder is not properly aligned with the telescope (see ALIGNING THE VIEWFINDER page 10).

Slew speed does not change when you press the SPEED key, or the telescope moves

slowly even though the fast slew speed is chosen:

• Verify that only one light is illuminated on the Electronic Controller. If more than one light is on or blinking,

the Mode function is active. Exit the Mode function by pressing and holding the MODE key until only one

light is on (see APPENDIX A, page 26).

• The battery power may be low (see ASSEMBLY INSTRUCTIONS, page 9).

Telescope does not track a celestial object:

• The telescope tracks celestial objects automatically only if it is placed in the polar mode (see APPENDIX A,

page 26) and the telescope is polar aligned (see POLAR ALIGNMENT, page 16) using the #880 (ETX-90EC),

#881 (ETX-105EC or ETX-125EC) Table Tripod, or #883 Deluxe Field Tripod (see OPTIONAL ACCESSORIES,

page 21). The more accurate the polar alignment, the longer the telescope’s motor drive holds an object in

the field of view of the eyepiece. If using the Alt/Az mode, track celestial objects by using the Arrow keys on

the Electronic Controller. Automatic tracking of objects in the Alt/Az mode requires the optional #497 Autostar

Computer Controller. Also the Horizontal and Vertical locks must be locked (page 6).

Images through the eyepiece appear unfocused or distorted:

• The magnification may be too high for the viewing conditions. Back off to a lower power eyepiece (see

UNDERSTANDING MAGNIFICATION, page 12).

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• If inside a warm house or building, move outside. Interior air conditions may distort terrestrial or celestial

images, making it difficult, if not impossible, to obtain a sharp focus. For optimal viewing, use the telescope

outside in the open air instead of observing through an open or closed window or screen.

• If viewing a land object on a warm day, heat waves will distort the image (see TERRESTRIAL OBSERVING,

page 12).

• For clear viewing of objects, turn the focus knob (8, Fig. 1) slowly since the “in-focus” point of a telescope

is precise. Turning the focus knob too quickly may cause the focus point to pass without notice.

• The optics within the telescope need time to adjust to the outside ambient temperature to provide the

sharpest image. To cool down the optics, set the telescope outside for 10 to 15 minutes before observing

begins.

Telescope moves off a terrestrial object while observing:

•

The motor drive may be activated (see CHANGING MODES, page 26).

•

Verify that the vertical and horizontal locks are tight (see TELESCOPE CONTROLS, page 8).

Telescope does not move past a certain point:

• The built-in vertical or horizontal rotational “stops” may have been reached (see NOTE with bullet ᕧ, page 6).

Telescope pauses when changing slew direction:

• This pause is normal (see ARROW KEYS, page 8).

A terrestrial object appears reversed left-for-right:

• An eyepiece in the standard 90° observing position (4, Fig. 1) reverses an object left-for-right: To view a

correctly oriented image requires the optional #932 Erecting Prism (see OPTIONAL ACCESSORIES, page

21).

Meade Customer Service

If you have a question concerning your ETX model, call the Meade Instruments Customer Service

Department at (949) 451-1450, or fax to (949) 451-1460. Customer Service hours are 8:30 AM to 4:30 PM,

Pacific Time, Monday through Friday. In the unlikely event that the ETX requires factory servicing or repairs,

write or call the Meade Customer Service Department first, before returning the telescope to the factory,

giving full particulars as to the nature of the problem, as well as your name, address, and daytime telephone

number. The great majority of servicing issues can be resolved by telephone, avoiding return of the

telescope to the factory.

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Slow-Motion Controls . . . . . . . . . electric, 4 speed, both axes

Optional Autostar Capability . . . . . . . . . . . . . . . . . . . . . . . yes

Hemispheres of operation . . . . . North and South, switchable

Bearings:

Specifications: ETX-90EC Astro Telescope

Optical design . . . . . . . . . . . . . . . . . . . Maksutov-Cassegrain

Primary mirror diameter . . . . . . . . . . . . . . . . . . 96mm (3.78”)

Clear aperture . . . . . . . . . . . . . . . . . . . . . . . . . . 90mm (3.5”)

Focal length. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1250mm

Focal ratio (photographic speed). . . . . . . . . . . . . . . . . . f/13.8

Near focus (approx) . . . . . . . . . . . . . . . . . . . . . 11.5 ft (3.5m)

Resolving power. . . . . . . . . . . . . . . . . . . . . . . . . 1.3 arc secs

Super multi-coatings (EMC) . . . . . . . . . . . . . . . . . . . standard

Limiting visual stellar magnitude (approx.). . . . . . . . . . . . 11.7

Image scale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.16°/inch

Maximum practical visual power . . . . . . . . . . . . . . . . . . 325X

Optical tube dimensions

Altitude . . . . . . . . . . . . . . . . . . . . . . . . . . . ball bearings

Azimuth. . . . PTFE thrust bearing and radial ball bearing

Materials:

Tube body . . . . . . . . . . . . . . . . . . . . . . . . . . . aluminum

Mounting . . . . . . ABS, with internal aluminum structure

Primary mirror . . . . . . . . . . . . . . . . . . . . . . Pyrex^®glass

Correcting lens. . . . . . . . . . . BK7 optical glass, Grade-A

Telescope dimensions:

. . . . . . . . . . . . . 43cm x 25cm x 20cm (17” x 10” x 8”)

Telescope net weight:

(dia. x length) . . . . . . . . . . 10.4cm x 27.9cm (4.1” x 11”)

Eyepiece. . . . . . . . . . . . . . . . . . . . . . . . . Super Plössl 26mm

Viewfinder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 x 21mm

Secondary mirror obstruction (dia.; %) . . 27.9mm (1.1”); 9.6%

Telescope mounting . . . . . . . . . . . . . . . fork type; double tine

Setting circle diameters . . . . . . . . . . . . . . . Dec.: 3.5”; RA: 7”

Input voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 volts DC

(incl. Electronic Controller & batteries) . . 6.1kg (13.5 lbs)

Telescope shipping weight. . . . . . . . . . . . . . . 8.3kg (18.4 lbs)

Battery Life (approx.):

with Electronic Controller . . . . . . . . . . . . . . . . . . . 45 hrs

with Autostar . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 hrs

Specifications: ETX-125EC Astro Telescope

Motor Drive System DC servo motors with encoders, both axes

Slow-Motion Controls . . . . . . . . . electric, 4 speed, both axes

Optional Autostar Capability . . . . . . . . . . . . . . . . . . . . . . . yes

Hemispheres of operation . . . . . North and South, switchable

Bearings:

Optical design . . . . . . . . . . . . . . . . . . . Maksutov-Cassegrain

Primary mirror diameter . . . . . . . . . . . . . . . . . 138mm (5.43”)

Clear aperture . . . . . . . . . . . . . . . . . . . . . . . . . 127mm (5.0”)

Focal length . . . . . . . . . . . . . . . . . . . . . . . . . 1900mm (74.8”)

Focal ratio (photographic speed) . . . . . . . . . . . . . . . . . . . f/15

Near focus (approx). . . . . . . . . . . . . . . . . . . . . . . 5.5m (18 ft)

Resolving power. . . . . . . . . . . . . . . . . . . . . . . . . 0.9 arc secs

Super multi-coatings (EMC) . . . . . . . . . . . . . . . . . . . standard

Limiting visual stellar magnitude (approx.). . . . . . . . . . . . 12.5

Image scale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.76°/inch

Maximum practical visual power . . . . . . . . . . . . . . . . . . 500X

Optical tube dimensions

Altitude. . . . . . . . . . . . . . . . . . . . . . UHMW polyethylene

Azimuth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . PTFE

Materials:

Tube body . . . . . . . . . . . . . . . . . . . . . . . . . . . aluminum

Mounting . . . . . . high-impact ABS, aluminum-reinforced

Primary mirror . . . . . . . . . . . . . . . . . . . . . . Pyrex^®glass

Correcting lens. . . . . . . . . . . BK7 optical glass, Grade-A

Telescope dimensions:

. . . . . . . . . . . . . . . . 38cm x 18cm x 22cm (15” x 7” x 9”)

Telescope net weight:

(dia. x length) . . . . . . . . . 14.6cm x 36cm (5.75” x 14.2”)

Eyepiece. . . . . . . . . . . . . . . . . . . . . . . . . Super Plössl 26mm

Viewfinder. . . . . . . . . . . . . . . . . . . . . . . 8 x 25mm right-angle

Secondary mirror obstruction (dia.; %) . . 39.4mm (1.6”); 9.6%

Telescope mounting . . . . . . . . . . . . . . . fork type; double tine

Setting circle diameters . . . . . . . . . . . . . . . Dec.: 4.3”; RA: 9”

Input voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 volts DC

Motor Drive System . . DC servo motors with encoders, both axes

Slow-Motion Controls . . . . . . . . . electric, 4 speed, both axes

Optional Autostar Capability . . . . . . . . . . . . . . . . . . . . . . . yes

Hemispheres of operation . . . . . North and South, switchable

Bearings:

(incl. Electronic Controller & batteries) . . 3.5kg (7.8 lbs)

Telescope shipping weight. . . . . . . . . . . . . . . 5.8kg (12.8 lbs)

Battery Life (approx.):

with Electronic Controller . . . . . . . . . . . . . . . . . . . 45 hrs

with Autostar . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 hrs

Specifications: ETX-105EC Astro Telescope

Optical design . . . . . . . . . . . . . . . . . . . Maksutov-Cassegrain

Primary mirror diameter . . . . . . . . . . . . . . . . . 116mm (4.56”)

Clear aperture . . . . . . . . . . . . . . . . . . . . . . . . 105mm (4.13”)

Focal length . . . . . . . . . . . . . . . . . . . . . . . . . 1470mm (57.8”)

Focal ratio (photographic speed) . . . . . . . . . . . . . . . . . . . f/14

Near focus (approx). . . . . . . . . . . . . . . . . . . . . . . 4.6m (15 ft)

Resolving power. . . . . . . . . . . . . . . . . . . . . . . . . 1.1 arc secs

Super multi-coatings (EMC) . . . . . . . . . . . . . . . . . . . standard

Limiting visual stellar magnitude (approx.). . . . . . . . . . . . 12.1

Image scale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.99°/inch

Maximum practical visual power. . . . . . . . . . . . . . . . . . . 420x

Optical tube dimensions

Altitude . . . . . . . . . . . . . . . . . . . . . . . . . . . ball bearings

Azimuth . . . . . . . . . . . . . . . . . . . . . . . . . . . ball bearings

Materials:

Tube body . . . . . . . . . . . . . . . . . . . . . . . . . . . aluminum

Mounting . . . . . . . ABS, with internal aluminum structure

Primary mirror . . . . . . . . . . . . . . . . . . . . . . Pyrex^®glass

Correcting lens. . . . . . . . . . . BK7 optical glass, Grade-A

Telescope dimensions:

. . . . . . . . . . 48cm x 23cm x 27cm (19” x 8.9” x 10.8”)

Telescope net weight:

(dia. x length) . . . . . . . . 12.4cm x 32.8cm (4.88” x 12.9”)

Eyepiece. . . . . . . . . . . . . . . . . . . . . . . . . Super Plössl 26mm

Viewfinder. . . . . . . . . . . . . . . . . . . . . . . 8 x 25mm right-angle

Secondary mirror obstruction (dia.; %). . . 3.3cm (1.32”); 9.4%

Telescope mounting . . . . . . . . . . . . . . . fork type; double tine

Setting circle diameters . . . . . . . . . . . . . Dec.: 3.81”; RA: 7.8”

Input voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 volts DC

Motor Drive System . . DC servo motors with encoders, both axes

(incl. Electronic Controller & batteries) . . 6.9kg (15.2 lbs)

Telescope shipping weight . . . . . . . . . . . . . . 11.4kg (25.2 lbs)

Battery Life (approx.):

with Electronic Controller . . . . . . . . . . . . . . . . . . . 45 hrs

with Autostar . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 hrs

- 25 -

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Appendix A: ADVANCED ELECTRONIC CONTROLLER FUNCTIONS

Tracking Motor Speeds

In the polar mode the Electronic Controller normally tracks objects at the sidereal rate (see SIDEREAL RATE, page

13). For most observing sessions (once the telescope has been polar aligned and the tracking motor activated),

there is little need to change this speed.

For objects, like the Moon or a comet, that move at slightly different rates, the Electronic Controller Arrow keys (1, Fig.

3) are sufficient to move the telescope slightly as the object very slowly moves off-center through the eyepiece field.

To change the tracking rate, for extended observations of an object not moving at the sidereal rate, follow the

procedure for the appropriate hemisphere:

Northern Hemisphere Polar:

Press and hold the MODE key (5, Fig. 3) until the Mode function is active (i.e., lights 1 and 2 are on steady;

lights 3 and 4 signify whatever tracking mode was last chosen).

Press the SPEED key (3, Fig. 3) until lights 1, 2, and 3 are on steady with light 4 blinking. The telescope is

now in the Northern Hemisphere polar mode.

Press the IN key (7, Fig. 3) and light 4 comes on steady. The tracking rate is now 0.5% faster than sidereal.

If the object you're tracking is moving faster than the sidereal rate, look through the eyepiece and continue to

press the IN key until the object remains centered with little or no drifting in the eyepiece.

Step 2.

Note: The tracking rate can be increased by up to 65% (127 presses of the IN key).

Step 4.

To use a rate slower than sidereal, press the OUT (6, Fig. 3) key until light 4 blinks again (sidereal rate). Press

the OUT key again and light 4 goes out, signifying a tracking rate 0.5% slower than sidereal. If the object

you're tracking is moving slower than the sidereal rate, look through the eyepiece and continue to press the

OUT key until the object remains centered with little or no drifting in the eyepiece.

Note: The tracking rate can be decreased by up to 65% (127 presses of the OUT key).

Press and hold the MODE key until only a single light is on. This exits the Mode function. If Northern or

Southern Hemisphere polar mode was chosen, the motor drive starts operating at the sidereal rate.

Use the four Arrow keys (1, Fig. 3) to slew the telescope to the desired object. To change the slew speed,

press the SPEED key.

Step 3.

Step 5.

Southern Hemisphere Polar:

Press and hold the MODE key (5, Fig. 3) until the Mode function is active (i.e., lights 1 and 2 are on steady;

lights 3 and 4 signify the tracking mode last chosen).

Press the SPEED key (3, Fig. 3) until lights 1 and 2 are on steady, light 3 is off, and Light 4 is blinking.

Press the IN key (7, Fig. 3) and light 4 comes on steady. The tracking rate is now 0.5% faster than sidereal.

If the object you're tracking is moving faster than the sidereal rate, look through the eyepiece and continue to

press the IN key until the object remains centered with little or no drifting in the eyepiece.

Note: The tracking rate can be increased by up to 65% (127 presses of the IN key).

Step 2.

Step 4.

To use a rate slower than sidereal, press the OUT key (6, Fig. 3) until light 4 blinks again (sidereal rate). Press

the OUT key again and light 4 goes out, signifying a tracking rate 0.5% slower than sidereal. If the object

you're tracking is moving slower than the sidereal rate, look through the eyepiece and continue to press the

OUT key until the object remains centered with little or no drifting in the eyepiece.

Note: The tracking rate can be decreased by up to 65% (127 presses of the OUT key).

Press and hold the MODE key until only a single light is on. This exits the Mode function. If Northern or

Southern Hemisphere polar mode was chosen, the motor drive starts operating at the sidereal rate.

Use the four Arrow keys (1, Fig. 3) to slew the telescope to the desired object. To change the slew speed,

press the SPEED key.

Step 5.

Step 3.

Changing Modes Using the Electronic Controller

The Electronic Controller is in the Alt/Az mode when activated, unless a mode screw has been removed. To use

the Electronic Controller to change to Northern or Southern Hemisphere polar mode, or to use Alt/Az mode with

one of the mode screws removed, use the following procedure:

Complete the POLAR ALIGNMENT PROCEDURE on page 16.

Complete steps 2 through 8 as described in TO MOVE THE TELESCOPE USING THE ELECTRONIC CONTROLLER,

page 15, to initialize the Electronic Controller.

Step 4.

Step 3.

Press and hold the MODE key (5, Fig. 3) until lights 1 and 2 are on steady and lights 3 and 4 start blinking.

Press the SPEED key (3, Fig. 3) once. This changes the system to polar mode for the Earth’s Southern

Hemisphere, with the motor drive set to operate at the sidereal rate.

Press the SPEED key a second time. This changes the system to polar mode for the Earth’s Northern

hemisphere, with the motor drive set to operate at the sidereal rate.

Press the SPEED key a third time and the system returns to the Alt/Az mode. In the Alt/Az mode the motor

drive does not activate when exiting from the Mode function.

Use the SPEED key as described in the above steps to cycle among these three modes (Alt/Az, Southern

Hemisphere polar, or Northern Hemisphere-polar) until the desired mode is shown by the appropriate light

configuration.

Step 5.

Step 6.

Step 8.

Press and hold the MODE key until just one light is on. This exits the Mode function. If you choose Northern

or Southern Hemisphere polar mode, the motor drive starts operating at the sidereal rate.

Use the four Arrow keys (1, Fig. 3) to slew the telescope to the desired object. To change the slew speed,

press the SPEED key.

- 26 -

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Appendix B: HELPFUL CHARTS

Latitude Chart for Major Cities of the World

Star Locator

To aid in the polar alignment procedure (see page 16), latitudes

of major cities around the world are listed below. To determine

the latitude of an observing site not listed on the chart, locate

the city closest to your site. Then follow the procedure below:

Following is a list of bright stars with their R.A. and Dec.

coordinates, along with the Northern hemisphere season when

these stars are prominent in the night sky. This list will aid the

observer to find alignment stars at various times of the year.

For example, if it is a midsummer evening in the Northern

hemisphere, Deneb in the constellation Cygnus, would be an

excellent alignment star, while Betelgeuse could not be used

because it is in the winter constellation Orion and thus below

the horizon.

Northern hemisphere observers (N): If the site is over 70

miles (110 km) north of the listed city, add one degree for every

70 miles. If the site is over 70 miles South of the listed city,

subtract one degree per 70 miles.

Southern Hemisphere observers (S): If the site is over 70

miles (110 km) north of the listed city, subtract one degree for

every 70 miles. If the site is over 70 miles South of the listed

city, add one degree per 70 miles.

Season Star Name Constellation R.A.

Dec.

Spring

Arcturus

Regulus

Spica

Boötes

Leo

Virgo

14h16m 19° 11"

10h09m 11° 58"

13h25m -11° 10"

NORTH AMERICA

City

State/Prov./Country Latitude

Summer Vega

Summer Deneb

Summer Altair

Summer Antares

Lyra

18h37m 38° 47"

20h41m 45° 17"

19h51m 08° 52"

16h30m -26° 26"

Albuquerque

Anchorage

Atlanta

Boston

Calgary

Chicago

Cleveland

Dallas

Denver

Detroit

New Mexico

35° N

61° N

34° N

42° N

51° N

42° N

41° N

33° N

40° N

42° N

21° N

32° N

39° N

45° N

36° N

35° N

34° N

19° N

26° N

45° N

36° N

30° N

41° N

35° N

45° N

40° N

33° N

46° N

41° N

29° N

33° N

38° N

47° N

39° N

Cygnus

Aquila

Scorpius

Alaska

Georgia

Massachusetts

Alberta

Illinois

Fall

Markab

Pegasus

23h05m 15° 12"

Fomalhaut Piscis Austrinus 22h58m -29° 38"

Mira

Ohio

Texas

Colorado

Michigan

Hawaii

Cetus

02h19m -02° 58"

Winter

Rigel

Betelgeuse Orion

Sirius

Aldebaran Taurus

Orion

05h15m -08° 12"

05h55m 07° 25"

06h45m -16° 43"

04h35m 16° 31"

Honolulu

Jackson

Kansas City

Kenosha

Canis Major

Mississippi

Missouri

Wisconsin

Nevada

SOUTH AMERICA

City

Bogotá

São Paulo

Buenos Aires

Montevideo

Santiago

Las Vegas

Little Rock

Los Angeles

Mexico City

Miami

Minneapolis

Nashville

New Orleans

New York

Oklahoma City

Ottawa

Philadelphia

Phoenix

Portland

Salt Lake City

San Antonio

San Diego

San Francisco

Seattle

Country

Colombia

Brazil

Argentina

Uruguay

Chile

Latitude

4° N

Arkansas

California

Mexico

23° S

35° S

34° S

10° N

Florida

Minnesota

Tennessee

Louisiana

New York

Oklahoma

Ontario

Caracas

Venezuela

ASIA

City

Beijing

Hong Kong

Seoul

Taipei

Tokyo

Sapporo

Bombay

Calcutta

Hanoi

Country

China

South Korea

Taiwan

Japan

India

Vietnam

Saudi Arabia

Latitude

40° N

23° N

37° N

25° N

36° N

43° N

19° N

22° N

21° N

Pennsylvania

Arizona

Oregon

Utah

Texas

California

Washington

District of Columbia

Washington

Jedda

EUROPE

City

Amsterdam

Athens

Bern

Copenhagen

Dublin

Frankfurt

Glasgow

Helsinki

Lisbon

London

Madrid

Oslo

Paris

Rome

AFRICA

City

Cairo

Cape Town

Rabat

Tunis

Country

Netherlands

Greece

Switzerland

Denmark

Ireland

Germany

Scotland

Finland

Portugal

England

Spain

Norway

France

Italy

Sweden

Austria

Poland

Latitude

52° N

38° N

47° N

56° N

53° N

50° N

56° N

60° N

39° N

51° N

40° N

60° N

49° N

42° N

59° N

48° N

52° N

Country

Egypt

South Africa

Morocco

Tunisia

Latitude

30° N

34° S

34° N

37° N

Windhoek

Namibia

23° S

AUSTRALIA AND OCEANIA

City

Adelaide

Brisbane

Canberra

Alice Springs

Hobart

Perth

Sydney

Melbourne

Auckland

State/Country

South Australia

Queensland

New South Wales

Northern Territory

Tasmania

Western Australia

New South Wales

Victoria

Latitude

35° S

27° S

35° S

24° S

43° S

32° S

34° S

38° S

37° S

Stockholm

Vienna

Warsaw

New Zealand

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Appendix C: PRECISE POLAR ALIGNMENT; SETTING CIRCLES

If desired, you may obtain more precise polar alignment by first accomplishing basic polar alignment as

detailed in POLAR ALIGNMENT PROCEDURE, page 16, then returning to this procedure:

Note: This procedure moves the telescope physically to line up precisely with the celestial pole.

Do not use the Electronic Controller Arrow keys to move the telescope electronically or polar

alignment will be lost.

Important Note:

For almost all

astronomical

observing

1. Orient the entire telescope, including tripod or tripod legs, so that the polar axis is pointing toward Polaris

(Fig. 14).

requirements,

2. While observing through the SP 26mm eyepiece of the telescope, adjust the length of the adjustable

tripod leg until Polaris is visible in the eyepiece. Use a combination of (a) lifting and turning the entire

telescope (or nudging the position of one of the fixed tripod legs) and (b) adjusting the length of the

adjustable tripod leg to place Polaris in the center of the telescope's field.

approximate settings

of the telescope’s

latitude and polar axis

are acceptable. Do

not allow undue

attention to precise

polar alignment of the

telescope to interfere

with your enjoyment

of the instrument.

3. Repeat step 2 of this procedure in about 15 minutes to see how much drift has taken place and to make

the alignment more precise.

Although the above procedure is somewhat tedious (since the field of view of the telescope with the SP

26mm eyepiece is only about 1°), it is a worthwhile effort if precise polar alignment is desired (e.g., if

photography of the Moon or a planet is to be performed). With Polaris placed in the center of the telescope’s

eyepiece, the telescope is now polar aligned within about one or two degrees, a level of alignment precision

more than sufficient for almost any observing application.

To provide the most stable platform from which to polar align the ETX models, it is recommended to

purchase the #883 Deluxe Field Tripod. The tripod head tilts easily to the local latitude angle for quick polar

alignment, and it locks in a 90° position to facilitate Alt/Az viewing (see OPTIONAL ACCESSORIES, page 20).

Setting Circles

The ETX models are equipped with R.A. and Dec. setting circles (13 and 16, Fig. 1) to aid in locating faint

celestial objects when the telescope has been polar aligned. Setting circles emulate the celestial

coordinates found on star charts or in sky catalogs. Any charted object is easily located by coordinates in

R.A. (in hours, minutes, and seconds, from 0h 0m 0s to 23h 59m 59s) and Dec. (in degrees from 0° to ±90°).

With an ETX model polar aligned, use the Electronic Controller Arrow keys (1, Fig. 3) to move the telescope

in R.A. (left and right keys) and Dec. (up and down keys).

Note: The Dec. setting circle is located on the left arm of the telescope fork mount. The right

arm of the mount contains a graduated circle (mounted behind the knurled knob of the vertical

lock), without Dec. numbers.

Fig. 31: Section of

Declination setting circle.

• Declination Setting Circle: The Dec. setting circle (Fig. 31) has been factory set to read the correct

Declination of celestial objects.

Because the smooth knob on this fork mount arm need never be loosened, the Dec. setting circle should

always remain calibrated. If for some reason this knob becomes loose and the Dec. setting circle must

be recalibrated, level the optical tube (5, Fig. 1) so that it is parallel to the drive base. Loosen the smooth

knob covering the Dec. setting circle until the setting circle moves freely. Reposition the setting circle so

that the 0 setting aligns with the Dec. pointer (5, Fig. 16). Retighten the Dec. knob.

Fig. 32: Section of Right

Ascension setting circle.

• Right Ascension Setting Circle: Since celestial objects move in R.A., the R.A. setting circle (Fig. 32)

must be reset as each object is located during an observing session. The R.A. pointer is located on the

drive base 90° counterclockwise from the telescope’s Computer Control panel (10, Fig. 1) immediately

under the R.A. circle.

To use the setting circles to find astronomical objects, the ETX must first be polar aligned. It is advisable

that the motor drive be turned on (see APPENDIX A, page 26) and that a low-power eyepiece (e.g., the SP

26mm eyepiece) be employed. Then use the following procedure:

Note: The R.A. circle

has two rows of

numbers from 0 to 23,

corresponding to the

hours of a 24-hour

clock. The upper row

of numbers is used by

observers in the

Earth’s Northern

Hemisphere, the

lower row by

1. Identify the celestial coordinates (R.A. and Dec.) of a bright, easy-to-find object, such as a bright star.

(Avoid using Polaris or any object near Polaris.) Coordinates of bright stars are listed in the STAR

LOCATOR, page 27, astronomy magazines, text books, or star charts. Center this object in the telescope’s

field of view.

2. Manually turn the R.A. circle (13, Fig. 1) to read the R.A. of the object at the R.A. pointer (7, Fig. 16).

3. The R.A. circle is now calibrated to read the correct R.A. of any object at which the telescope is pointed.

The Dec. circle is already calibrated through polar alignment.

4. To find another object, again identify the R.A. and Dec. coordinates. Then, without touching the setting

circles, move the telescope (manually, by unlocking the vertical and horizontal locks, or by slewing the

telescope using the Electronic Controller Arrow keys) so that the R.A. and Dec. pointers read the

coordinates of the second object.

observers in the

Earth’s Southern

Hemisphere.

5. If the above procedure has been followed carefully, the second object will now be in the telescope’s field

of view.

Note: Since the second object (i.e., the object to be located) is in constant motion, once the

R.A. circle is calibrated (step 2, above) the telescope should be moved rapidly to read the

coordinates of the second object. Otherwise the second object will no longer be in the position

indicated by the R.A. circle.

Using setting circles requires a developed technique. When using the circles for the first time, try hopping

from one bright star (the calibration star) to another bright star of known coordinates. Practice moving the

telescope from one easy-to-find object to another. In this way the precision required for accurate object

location becomes familiar.

- 28 -

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Appendix D: YOU AND THE UNIVERSE

OBJECTS IN SPACE

In the early 17th century, Italian Scientist Galileo, using a crude telescope considerably smaller than the

ETX-90EC, turned it to look towards the sky instead of distant trees and mountains. What he saw, and what

he realized about what he saw, forever changed the way mankind thinks of the universe. Imagine what it

must have been like being the first human to see moons revolve around the planet Jupiter or to see the

changing phases of Venus! Because of his observations, Galileo correctly realized Earth's movement and

position around the Sun, and in doing so, gave birth to modern astronomy. Yet Galileo's telescope was so

crude, he could not clearly make out the rings of Saturn.

Galileo's discoveries laid the foundation for understanding the motion and nature of the planets, stars, and

galaxies. Building on his foundation, Henrietta Leavitt determined how to measure the distance to stars;

Edwin Hubble proposed a glimpse into the origin of the universe; Albert Einstein unraveled the relationship

of time and light; and 21st-century astronomers are currently discovering planets around stars outside our

solar system. Almost daily, using sophisticated successors to Galileo's crude telescope, such as the Hubble

Space Telescope and the Chandra X-ray telescope, more and more mysteries of the universe are being

solved and understood. We are living in the golden age of astronomy.

Unlike other sciences, astronomy welcomes contributions from amateurs. Much of the knowledge we have

on subjects such as comets, meteor showers, variable stars, the Moon, and our solar system comes from

observations made by amateur astronomers. So as you look through your Meade ETX telescope, keep in

mind Galileo. To him, a telescope was not merely a machine made of glass and metal, but something far

more—a window through which the beating heart of the universe might be observed.

Autostar Glossary

If you're using the optional #497 Autostar handbox, be sure to make use of Autostar’s Glossary feature. The

Glossary menu provides an alphabetical listing of definitions and descriptions of common astronomical

terms. Access directly through the Glossary menu or through hypertext words embedded in Autostar. See

the Autostar manual for more information.

Listed below are some of the many astronomical objects that can be seen with your ETX telescope.

The Moon

The Moon is, on average, a distance of 239,000 miles (380,000km) from Earth and is best observed during

its crescent or half phase when Sunlight strikes the Moon’s surface at an angle. It casts shadows and adds

a sense of depth to the view (Fig. 33). No shadows are seen during a full Moon, causing the overly bright

Moon to appear flat and rather uninteresting through the telescope. Be sure to use a neutral Moon filter

when observing the Moon. Not only does it protect your eyes from the bright glare of the Moon, but it also

helps enhance contrast, providing a more dramatic image.

Using your ETX model, brilliant detail can be observed on the Moon, including hundreds of lunar craters and

maria, described below.

Fig. 33: The Moon.

Note the deep

shadows in the craters.

Craters are round meteor impact sites covering most of the Moon’s surface. With no atmosphere on the

Moon, no weather conditions exist, so the only erosive force is meteor strikes. Under these conditions, lunar

craters can last for millions of years.

Maria (plural for mare, seas) are smooth, dark areas scattered across the lunar surface. These areas are

ancient impact basins that were filled with lava from the interior of the Moon by the depth and force of the

meteor or comet impact.

12 Apollo astronauts left their bootprints on the Moon in the late 1960’s and early 1970’s. However, no

telescope on Earth can see these footprints or any other artifacts. In fact, the smallest lunar features that

may be seen with the largest telescope on Earth are about one-half mile across.

Note: Except during its early or late crescent phases, the Moon can be an exceptionally bright object to view

through the telescope. To reduce the brightness and glare, use the #905 Variable Polarizing Filter (see the

MEADE GENERAL CATALOG for more information).

Planets

Planets change positions in the sky as they orbit around the Sun. To locate the planets on a given day or

month, consult a monthly astronomy magazine, such as Sky and Telescope or Astronomy. Listed below are

the best planets for viewing through your ETX model telescope.

Venus is about nine-tenths the diameter of Earth. As Venus orbits the Sun, observers can see it go through

phases (crescent, half, and full) much like those of the Moon. The disk of Venus appears white, as sunlight

is reflected off the thick cloud cover that completely obscures any surface detail.

Mars is about half the diameter of Earth. Through the telescope it appears as a tiny reddish-orange disk.

You may see a hint of white at one of the planet’s polar ice caps. Approximately every two years, when Mars

is closest to Earth, additional detail and coloring on the planet's surface may be visible.

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Jupiter (Fig. 34) is the largest planet in our

solar system, with a diameter 11 times that of

Earth. Jupiter appears as a disk with dark lines

stretching across the surface. These lines are

cloud bands in the atmosphere. Four of

Jupiter’s 29 (and still counting!) moons (Io,

Europa, Ganymede, and Callisto) can be seen

as star-like points of light when you use even

the lowest magnification. The number of moons

visible on any given night changes as they

circle around the giant planet.

FOR BEGINNERS

TIPS

Further Study....

This manual gives only the briefest introduction to

astronomy. If you are interested in pursuing further

studies in astronomy, a few topics are suggested

below that are worth reading up on. Try looking up

some of these in the optional Autostar glossary.

Fig. 34: Jupiter and

its four largest

moons. The moons

can be observed in

a different position

every night.

Also included below is a small sampling of books,

magazines, and organizations that you might find

helpful.

Saturn (Fig. 35) is nine times the diameter of

Earth and appears as a small, round disk with

rings extending out from either side. In 1610,

Galileo, the first person to observe Saturn

through a telescope, did not understand that

what he was seeing were rings. Instead, he

believed that Saturn had “ears.” Saturn’s rings

are composed of billions of ice particles. The

major division in Saturn's rings, called the

Cassini Division, is generally visible through all

three ETX models. Titan, the largest of Saturn’s

moons, can also be seen as a bright, star-like

object near the planet.

Topics

1. How is a star born? How does a solar system

form?

2. How is the distance to a star measured? What

is a light year? What is red shift and blue shift?

3. How are the craters on our Moon formed? How

old is the Moon and Earth? How old is the Sun?

Fig. 35: Saturn has

the most extensive

ring structure in our

Solar System.

4. What is a black hole? A neutron star?

5. What are stars made of? Why are stars

different colors? What is a white dwarf? A red

giant? Have we ever seen the surface of a star

besides our own sun?

Deep-Sky Objects

You can use star charts to locate constellations,

individual stars, and deep-sky objects.

Examples of various deep-sky objects are

given below:

6. What is a nova? A supernova?

7. What are comets? Minor planets? Meteors?

Meteor showers? Where do they come from?

8. What is a planetary nebula? A globular cluster?

Stars are large gaseous objects that are

illuminated by nuclear fusion in their core.

Because of their vast distances from our solar

system, all stars appear as pinpoints of light,

regardless of the size of the telescope used.

9. What is the Big Bang? Is the universe

expanding or contracting, or does it always

remain the same? What is dark matter?

10. What is an extrasolar planet? What is an

accretion (or protoplanetary) disk?

Nebulae are vast interstellar clouds of gas and

dust where stars are formed. Most impressive

of these is the Great Nebula in Orion (M42), a

diffuse nebula that appears as a faint wispy

gray cloud. M42 is 1600 light years from Earth.

11. What is the difference between an elliptical, a

spiral, and an irregular galaxy?

Books

1. The Guide to Amateur Astronomy by Jack

Newton and Philip Teece

Open Clusters are loose groupings of young

stars, all recently formed from the same diffuse

nebula. The Pleiades (Fig. 36) is an open

cluster 410 light years from Earth. Several

hundred stars of the cluster are visible through

the your telescope.

2. The Sky: A User’s Guide by David Levy

3. Turn Left at Orion by Guy Consolmagno & Dan

Davis

4. Astrophotography for the Amateur by Michael

Covington

Constellations are large, imaginary patterns of

stars believed by ancient civilizations to be the

celestial equivalent of objects, animals, people,

or gods. These patterns are too large to be

Magazines

1. Sky & Telescope

Box 9111, Belmont, MA 02178

2. Astronomy

Fig. 36: The

Pleiades is one of

the most beautiful

open clusters.

seen through

telescope. To learn the

Box 1612, Waukesha, WI 53187

constellations, start with an easy grouping of

stars, such as the Big Dipper in Ursa Major.

Then use a star chart to explore across the sky.

Organizations:

1. Astronomical League

Executive Secretary

Galaxies are large assemblies of stars,

nebulae, and star clusters that are bound by

gravity. The most common shape is spiral (such

as our own Milky Way), but galaxies can also

be elliptical, or even irregular blobs. The

Andromeda Galaxy (M31) is the closest spiral-

type galaxy to our own. This galaxy appears

fuzzy and cigar-shaped. It is 2.2 million light

years away in the constellation Andromeda.

5675 Real del Norte, Las Cruces, NM 88012

2. The Astronomical Society of the Pacific

390 Ashton Ave, San Francisco, CA 94112

3. The Planetary Society

65 North Catalina Ave, Pasadena, CA 91106

And watch Jack Horkheimer, Star Gazer, on your

local PBS station.

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MEADE LIMITED WARRANTY

Every Meade telescope, spotting scope, and telescope accessory is warranted by Meade Instruments Corporation (“Meade”)

to be free of defects in materials and workmanship for a period of ONE YEAR from the date of original purchase in the U.S.A.

and Canada. Meade will repair or replace a product, or part thereof, found by Meade to be defective, provided the defective

part is returned to Meade, freight-prepaid, with proof of purchase. This warranty applies to the original purchaser only and is

non-transferable. Meade products purchased outside North America are not included in this warranty, but are covered under

separate warranties issued by Meade international distributors.

RGA Number Required: Prior to the return of any product or part, a Return Goods Authorization (RGA) number must be

obtained from Meade by writing, or by calling (949) 451-1450. Each returned part or product must include a written statement

detailing the nature of the claimed defect, as well as the owner’s name, address, and phone number.

This warranty is not valid in cases where the product has been abused or mishandled, where unauthorized repairs have been

attempted or performed, or where depreciation of the product is due to normal wear-and-tear. Meade specifically disclaims

special, indirect, or consequential damages or lost profit which may result from a breach of this warranty. Any implied

warranties which cannot be disclaimed are hereby limited to a term of one year from the date of original retail purchase.

This warranty gives you specific rights. You may have other rights, which vary from state to state.

Meade reserves the right to change product specifications or to discontinue products without notice.

This warranty supersedes all previous Meade product warranties.

WARNING

This equipment has been tested and found to comply with the limits for a CLASS B digital device, pursuant to Part 15 of

the FCC Rules. These limits are designed to provide reasonable protection against harmful interference in a residential

installation. This equipment generates, uses, and can radiate radio frequency energy and, if not installed and used in

accordance with the instructions contained in this manual, may cause harmful interference to radio and television

communications. However, there is no guarantee that interference will not occur in a particular installation.

If this equipment does cause harmful interference to radio or television reception, which can be determined by turning

the equipment off and on, the user is encouraged to try to correct the interference by one or more of the following

measures:

• Reorient or relocate the receiving antenna.

• Increase the separation between the equipment and the receiver.

• Connect the equipment into an outlet on a circuit different from that of the receiver.

• Consult the dealer or an experienced audio/television technician.

Note: Connecting this device to peripheral devices that do not comply with CLASS B requirements or using an unshielded

peripheral data cable could also result in harmful interference to radio or television reception.

The user is cautioned that any changes or modifications not expressly approved by the party responsible for compliance

could void the user’s authority to operate this equipment.

To ensure that the use of this product does not contribute to interference, it is necessary to use shielded I/O cables.

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P R O D U C T S D I V I S I O N

^AM^De^Va^{A N}d^Ce^{E D}Instruments Corporation

World’s Leading Manufacturer of Astronomical Telescopes for the Serious Amateur

6001 Oak Canyon, Irvine, California 92618 I (949) 451-1450

FAX: (949) 451-1460 I www.meade.com

Ver. 0501 Part no. 14-1010-20

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