|IMPORTANT NOTICE! Never use a telescope or spotting scope to look at the Sun! Observing the Sun, even for the shortest fraction of a second, will cause irreversible damage to your eye as well as physical damage to the telescope or spotting scope itself. |
The Meade ETX is an extremely versatile, high-resolution
telescope designed for everyone. Unlike larger or more
specialized telescopes that might appeal only to the advanced
amateur astronomer, the ETX is an easy-to-operate telescope
with fingertip controls, an internal motor drive for automatic
tracking of astronomical objects, and one of the finest optical
systems ever manufactured for a commercial telescope.
As a first telescope, the ETX reveals nature in an
everexpanding level of detail: observe the feather structure of
a bird from 50 yards or study the rings of the planet Saturn
from a distance of 800 million miles. The Meade ETX is an
instrument fully capable of growing with the user's interests.
For many, the ETX is all the telescope ever required.
As a second telescope for the amateur astronomer who may
already own a larger instrument, the ETX represents extreme
portability without sacrificing the most demanding requirements
for optical quality and field performance.
The result of more than five years in development by an elite
team of Meade optical designers and engineers, the Meade
ETX is, without question, one of the most revolutionary
telescopes to be developed in the past 25 years. We urge the
ETX user to read this manual thoroughly, in order that you
might avail yourself of all the designed-in features at your
disposal with this amazing instrument.
Fig. 1: The ETX Astro Telescope
- Viewfinder Alignment Screws
- 90° Eyepiece Holder
- Focus Knob
- Photo Port
- Flip-Mirror Control Knobs
- 1/4-20 Photo Tripod Adapter Block
- Fork Mount
- R.A. Slow-Motion Control
- R.A. Lock
- Attachment Holes for Fixed Tripod Legs
- Bottom Surface of Drive Base
- Drive Base
- R.A. (Right Ascension) Setting Circle
- Dec Slow-Motion Control
- Declination Pointer
- Dec (Declination) Setting Circle
- Screws for Attaching Optical Tube to Fork Mount
- Declination Cover Plate
- Declination Lock
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In keeping with the ETX philosophy of elegant simplicity, the
ETX is virtually completely assembled 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 included with the ETX Astro
- The ETX Astro Telescope with fork mount system.
- 8 x 21mm Viewfinder, packed in a separate, small box.
- Super Plössl (SP) 26mm eyepiece, packed in plastic storage container.
- Table Tripod legs (3 pcs), packed in a plastic bag.
- Hex-wrench set with 3 (English-format) wrenches, packed with the manual.
- The 8 x 21mm Viewfinder is packed separately from the main telescope in shipment to avoid the possibility of the viewfinder slipping in its bracket and scratching the viewfinder tube.
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2. Assembly Instructions
For assembly, have at your access a Phillips-head
screwdriver and three AA-size batteries. Basic assembly of
the telescope requires only a few steps:
NOTE. The viewfinder should be checked for correct focus
prior to installation in the viewfinder bracket. See telescope use, point 5a, below.
- Slide the viewfinder into its bracket (5, Fig. 2) with the
rubber-eyecup-end of the viewfinder fitting first through
the front end of the bracket. It may be necessary to
slightly unthread the six alignment screws (4 and 6, Fig.
2) to fit the viewfinder into the bracket. With the
viewfinder inside the bracket, tighten (to a firm feel only)
the six alignment screws down against the viewfinder tube. Alignment of
the viewfinder is detailed in this manual.
Fig. 2: The Viewfinder. (1) Lens Cell; (2) Knurled Lock-
Ring; (3) Viewfinder; (4) Front Alignment Screws; (5)
Viewfinder Bracket; (6) Rear Alignment Screws.
- Remove the SP 26mm eyepiece (1, Fig. 1) from its plastic
storage container and place it in the telescope's
eyepiece holder (4, Fig. 1) tightening the eyepiece-
holder's thumbscrew to a firm feel only.
- With the telescope lying on your lap or on the floor, use a
Phillips-head screwdriver to remove the three screws (1,
Fig. 3) that attach the metal base plate (5, Fig. 3) to the
bottom of the drive base (6, Fig. 3). Thread the center
tripod leg (the leg with the latitude scale) in to the central
hole (3, Fig. 3) of the metal base plate. Then, using the
tripod leg to hold the base plate, carefully pull the base
plate from the drive base.
- Insert three AA-size batteries in the battery clips located
inside the drive base (be careful to avoid touching the thin
wires leading from the battery mounting board to the
motor). Orient the batteries as shown on the battery
mounting board (Fig. 4). Then re-attach the metal base
plate to the bottom of the drive base using the three screws
(1, Fig. 3). Unthread the center tripod leg.
Basic assembly of the ETX is now complete.
Fig. 3: Bottom Surface of the Drive Base. (1) Attachment
Screws; (2) Upper Hole; (3) Center Hole; (4) Lower Hole;
(5) Base Plate; (6) Drive Base; (7) North-South Switch; (8)
Fig. 4: Showing three AA-size batteries installed inside the drive base.
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1. Quick Tips
- Viewfinder Alignment with Main Telescope: When first attached
to the telescope, the viewfinder and main optical tube are not
aligned. Therefore, it is not possible to locate objects in the main
telescope using the viewfinder. Procedures for aligning the
viewfinder and main telescope are discussed below.
- Declination and R.A. Controls: With the ETX sitting on a table,
as shown in Fig. 1, the Declination controls are used to move the
telescope vertically (up and down). The Right Ascension controls
are used to move the telescope horizontally (side to side).
Move Knobs Slowly: When making adjustments in R.A., Dec, or
focusing, turn the controls slowly. Moving the controls too quickly
may result in losing the object or passing the focus point.
Moving the ETX Astro Telescope: The ETX optical tube is not
designed to rotate a full 360° through its fork arms. The viewfinder
bracket contacts one of the fork arms at a point just past the 90°
position of the optical tube in the fork arms. Do not attempt to
force the telescope tube past this point or damage to the viewfinder
bracket will result.
- A Note on Indoor Viewing: While casual, low-power observations
may be made with the telescope through an open or closed window,
the best observing is always done outdoors. Temperature
differences between inside and outside air and/or the low quality of
most home window glass can cause blurred images through the
telescope. Do not expect high-resolution imaging under these
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2. Telescope Controls
An important array of controls facilitates operation of the ETX telescope.
Be sure to acquaint yourself with all of these controls before attempting
observations through the telescope.
R.A. Lock (11, Fig. 1): With the ETX sitting on a table as shown in Fig.
1, this control locks the telescope from moving horizontally. Turning the
R.A. Lock counterclockwise unlocks the telescope horizontally, enabling
the telescope to be freely moved by hand in a horizontal direction.
Turning the R.A. Lock clockwise locks the telescope in horizontal position.
R.A. Slow-Motion Control (10, Fig. 1): With the R.A. Lock in the
unlocked position, the R.A. Slow-Motion Control may be used for manual
slewing of the telescope in a horizontal direction. The R.A. Slow-Motion
Control should never be turned when the R.A. Lock is in the
locked position; damage to the internal gears may otherwise
result. The R.A. Lock must be engaged for the motor drive to track on
Dec Lock (21, Fig. 11): With the ETX sitting on a table as shown in Fig.
1, this control locks the telescope from moving vertically. (The definition
of "Dec," or "Declination," is explained further below.) Turning the Dec Lock
clockwise (to a firm feel only) locks the telescope in the vertical position.
Turning the Dec Lock about one full turn counterclockwise permits
manual motion of the telescope in the vertical position.
Dec Slow-Motion Control (16, Fig. 1): With the Dec Lock in the
locked position, the Dec Slow-Moton Control may be used for fine
motions of the telescope in a vertical direction. The Dec Slow-Motion
Control has a fixed travel length. At some point after turning the Dec
Slow-Motion Control continuously in the same direction, the control will
become difficult to turn. Do not attempt to turn the Dec Slow-Motion
Control past this point or damage to the internal mechanism will
result. Instead, back-off the Dec Slow-Motion Control by turning the
control about 50 turns in the opposite direction. Unlock the Dec Lock and
move the telescope manually to center the object; then resume use of
the Dec Slow-Motion Control.
Focus Knob (5, Fig. 1): Turning this knob causes a finely controlled
internal motion of the telescope's primary mirror to achieve precise
focus of the image. The ETX can be focused on objects from a distance
of about 11.5 ft (3.5m) to infinity. Rotate the focus knob clockwise to
focus on distant objects; rotate the focus knob counterclockwise to
focus on near objects.
Flip-Mirror Control (7, Fig. 1): The ETX includes an internal optically-flat mirror. The Flip-Mirror Control
is in the "up" position when the control is vertical (perpendicular to the
main telescope tube). It is "down" when the outer edge of the control is
horizontal (parallel with the main tube of the telescope).
With the Flip-Mirror Control in the "up"
position, light is diverted, at a 90° angle, to the eyepiece. Alternately,
with the Flip-Mirror Control in its "down" position, light proceeds straight
through the telescope and out the Photo Port (6, Fig. 1), for photography
using the #64 T-Adapter, or for observing with the #932 45° Erecting
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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: Generally speaking, telescope focal length is
the distance that light travels inside the telescope before reaching a
focus. In the mirror-lens design of the ETX, however, this focal length is,
in effect, compressed by the telescope's secondary mirror, so that a
long effective telescope focal length is housed in the short ETX optical
tube. The ETX's focal length is 1250mm, or about 49". If the ETX were a
classical refracting-type of telescope, its optical tube would thus be
more than four feet long instead of the ETX's compact 11" tube length.
Eyepiece Focal Length: The 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. The Meade ETX is supplied
with one eyepiece as standard equipment, a Super Plössl (SP) 26mm
eyepiece. Thus, the focal length of the provided eyepiece is 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
Technical note to the advanced amateur astronomer:
The SP 26mm eyepiece supplied with Meade ETX telescopes is
a special low-profile version of the standard Meade SP 26mm
eyepiece and is about 114" (6mm) shorter than the standard
eyepiece. This low-profile SP 26mm is designed to harmonize
with the ultracompact scale of the ETX telescope and utilizes
the exact same optics as the standard SP 26mm eyepiece. The
SP 26mm low-profile eyepiece is not parfocal, however, with
other eyepieces in the SP series (i.e., the eyepiece requires
refocusing when it is interchanged with other SP eyepieces).
Calculating Magnification: On a given 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, as stated above, yields
48X. Optional eyepieces and the #126 2X
Barlow Lens are available for powers from 31X to over 300X.
To calculate the magnification obtained with a given eyepiece,
use this formula:
||Telescope Focal Length
|Eyepiece Focal Length
Example: The power obtained with the ETX with the SP 26mm eyepiece is:
The most common mistake of the beginning observer is to
"overpower" the telescope by using high magnifications which
the telescope's aperture and typical atmospheric conditions
can not reasonably support. Keep in mind that a smaller, but
bright and well-resolved image is superior to one that is larger,
but dim and poorly resolved. Powers above 300X should be
employed with the ETX only under the steadiest atmospheric
Most observers will want to have 3 or 4 eyepieces and the
#126 2X Barlow Lens to achieve the full range of reasonable
magnifications possible with the ETX.
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4. First Observations
Unthread the metal dust cap from the front lens, and the ETX
Astro Telescope may now be used for terrestrial (land)
observing. Keep in mind, however, that the viewfinder has not
been aligned, and it will be necessary to locate objects simply
by sighting along the main telescope tube. With the SP 26mm
eyepiece inserted in to the telescope's eyepiece holder, the
telescope is operating at 48-power (written "48X").
Objects viewed through the eyepiece will be correctly oriented
up-and-down in the telescope but will be reversed left-for-right.
Image orientation is discussed in more detail below.
The Flip-Mirror Control (7, Fig. 1) must be in the "up" position in
order to observe a correctly-oriented image through the
After familiarizing yourself with the telescope's controls, make
your first observations of a simple land object7mdash;a telephone
pole or building, perhaps, several hundred yards in the
distance. Sight along the side of the telescope's main tube to
locate the object. Practice focusing on the object and centering
it in the field of view using the R.A. Slow-Motion Control and
Dec Slow Motion Control.
Note: The dust cap should be replaced after each observing
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5. The Viewfinder
The ETX, as with almost all astronomical telescopes, presents
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
lowpower, wide-field sighting scope with crosshairs that
enable the easy centering of objects in the main telescope's
field. Standard equipment with the ETX is a viewfinder of 8-power
and 21mm aperture, called an "8 x 21mm viewfinder."
The ETX viewfinder, unlike most telescope viewfinders,
presents a correctly oriented image, both up-and-down and
left-to-right. This orientation particularly facilitates the location
of terrestrial objects. The 8 x 21mm viewfinder is also a
tremendous aid in locating faint astronomical objects before
their observation in the main telescope.
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a. Focusing the Viewfinder
The ETX viewfinder has been factory pre-focused to objects
located at infinity. Individual eye variations, however, may
require that the viewfinder be re-focused for your eye. Prior to
installing the viewfinder in the viewfinder bracket (5, Fig. 2),
check the focus by looking through the viewfinder. Point the
viewfinder at a distant object; if the viewfinder image is not
sufficiently in focus for your eye, it may be re-focused as
- Loosen the knurled lock-ring (2, Fig. 2) located near the
viewfinder's objective (front) lens (1, Fig. 2). Unthread
this ring (counterclockwise, as seen from the eyepiece-
end of the viewfinder) by several full turns.
- Focus the viewfinder by rotating the objective lens cell (1,
Fig. 2) in one direction or the other, until distant objects
observed through the viewfinder appear sharp. One or
two rotations of the viewfinder lens have a significant
effect on image focus.
- Once correct focus is reached, lock the focus in place by
threading the knurled lock-ring snugly clockwise up
against the viewfinder's lens cell.
- Place the viewfinder into the viewfinder bracket (5, Fig.
2) on the main telescope. Gently tighten the six alignment
screws (4 and 6, Fig. 2), then proceed with alignment of
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b. Alignment of the Viewfinder
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 place. To
align the viewfinder follow this procedure:
- The viewfinder bracket (5, Fig. 2) includes six alignment
screws (4 and 6, Fig. 2). Turn the 3 rear-most alignment
screws (6, Fig. 2) so that the viewfinder tube is roughly
centered within the viewfinder bracket, as viewed from
the eyepiece-end of the telescope.
Note: Do not overtighten the alignment screws. When
tightening one screw it may be necessary to loosen one of the
two other screws.
- Using the SP 26mm eyepiece, point the main telescope at
some easy-to-find, well-defined land object, such as the
top of a telephone pole. Center the object precisely in the
main telescope's field and engage the R.A. Lock and Dec
Lock so that the object can not move in the field.
- While looking through the viewfinder, turn one or more of
the 3 front-most viewfinder alignment screws (4, Fig. 2),
until the crosshairs of the viewfinder point at precisely
the same position as the main telescope.
Re-check that the viewfinder's crosshairs and the main
telescope are now pointing at precisely the same object. The
viewfinder is now aligned to the main telescope. Unless the
alignment screws are disturbed, the viewfinder will remain
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c. Using the Viewfinder
To locate any object, terrestrial or astronomical, first center the
object in the crosshairs of the viewfinder; the object will then
also be centered in the field of the main telescope.
Note: If you intend to use higher observing magnifications,
first locate, center, and focus the object using a low-power
eyepiece (e.g., the SP 26mm eyepiece). Objects are easier to
locate and center at low powers; higher power eyepieces may
then be employed simply by changing eyepieces.
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1. Terrestrial Observing
The ETX Astro Telescope makes an excellent, high-resoluton
terrestrial (land), telescope. Simply by setting the telescope on
its drive base, as shown in Fig. 1, the telescope may be used
for an extremely wide range of land observations. Keep in
mind, however, that terrestrial images through the ETX Astro
Telescope will be right-side-up, but reversed left-for-right.
Normally, such an image orientation is not bothersome, unless
the observer is trying to read a distant sign, for example. If the
telescope is to be used for extensive terrestrial observations,
the optional #932 45° Erecting Prism, which yields a
correctly oriented image, is recommended.
Viewing terrestrial objects require observers to look along the
Earth's surface through heat waves. These heat waves often
cause degradation of image quality. Low power eyepieces, like
the SP 26mm eyepiece provided with the ETX Astro Telescope,
magnify these heat waves less than higher powered
eyepieces. Therefore, low power eyepieces provide a
steadier, higher quality image. If the land image is fuzzy or
ill-defined, drop down to a lower power, where the Earth's heat
waves will not have such a deleterious effect on image quality.
Observing in early morning hours, before the Earth has built up
internal heat, is generally more advantageous than during
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a. Mounting for Terrestrial Applications
For use in terrestrial viewing situations the ETX Astro
Telescope may be mounted in one of four ways:
- Set the telescope's drive base on a table or other steady
plafform, as discussed immediately above and as shown
in Fig. 1.
- Attach the telescope to the optional Meade ETX Field
Tripod as detailed in the instructions included with the
tripod and as shown in Figure 5. This tripod was exclusively
designed for the ETX Astro Telescope to provide
extremely stable mounting not available with standard
Fig. 5: Mounting the ETX Astro Telescope to the optional ETX Field
- Alternately, attach the entire ETX Astro Telescope (including fork
mount), to a heavy-duty photo tripod. Attachment to a
photo tripod is effected by means of the threaded hole (3,
Fig. 3) in the center of the bottom surface of the
telescope's drive base. This central hole is threaded with the
phototripod-standard 1/4-20 thread. We emphasize,
however, that only a strong, heavy-duty photo tripod,
designed to accept the weight of the 9 lb. (4.1 kg) ETX
Astro Telescope should be used in this application. Check
with the tripod manufacturer to confirm that the intended
tripod is designed to carry such a weight safely and
securely, before mounting the telescope in this way.
- The optical tube assembly of the ETX Astro Telescope
may also be removed from its fork mounting, allowing the tube
assembly to be placed directly on to a standard photo
tripod. To remove the tube assembly from its fork mount,
use one of the hex-wrenches packed with the telescope
to unthread the two attachment screws (19, Fig. 1)
located on each side of the optical tube's rear cell. Then
carefully slide the tube assembly out of the fork arms in
the direction of the telescope's eyepiece-end. The ETX's
rear-cell includes a tripod adapter plate (8, Fig. 1) for
attaching the tube assembly directly to the 1/4-20 thread
of any standard photo tripod.
Never use the ETX telescope to look at the Sun!
Observing the Sun, even for the shortest fraction of
a second, will cause Instant and Irreversible damage
to the eye, as well as physical damage to the
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2. Astronomical Observing
Used as an astronomical instrument, the ETX Astro Telescope
allows full use of its many optical and electromechanical
capabilities. It is in astronomical applications where the ETX's
extremely 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.
Understanding how and where to locate celestial objects, and
how those objects move across the sky is fundamental to
enjoying the hobby of astronomy. This section provides a
basic introduction to the terminology associated with
astronomy, and includes instructions for finding and following
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a. Celestial Coordinates
Celestial objects are mapped according to a coordinate system
on the Celestial Sphere (Fig. 6), an imaginary sphere
surrounding Earth on which all stars appear to be placed. This
celestial object mapping system is analogous to the
Earth-based coordinate system of latitude and longitude.
The poles of the celestial coordinate system are defined as
those two points where the Earth's rotational axis, if extended
to infinity, north and south, intersect the celestial sphere. Thus,
the North Celestial Pole is that point in the sky where an
extension of the Earth's axis through the North Pole intersects
the celestial sphere. This point in the sky is located near the
North Star, Polaris.
Fig. 6: Celestial Sphere.
In mapping the surface of the Earth, lines of longitude are
drawn between the North and South Poles. Similarly, lines of
latitude are drawn in an east-west direction, parallel to the Earth's
Equator. The Celestial Equator is a projection of the Earth's
Equator onto the celestial sphere.
Just as on the surface of the Earth, in mapping the celestial
sphere, imaginary lines have been drawn to form a coordinate
grid. Thus, object positions on the Earth's surface are specified
by their latitude and longitude. For example, you could locate
Los Angeles, California, by its latitude (+34°) and longitude
(1180); similarly, you could locate the constellation Ursa Major
(which includes the Big Dipper) by its general position on the
R.A.: 11hr; Dec: +50°.
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- Declination: The celestial analog to Earth latitude is called
Declination, or "Dec", and is measured in degrees, minutes
and seconds (e.g., 15° 27'33"). Declination shown as
north of the celestial equator is indicated with a "+" sign in
front of the measurement (e.g., the Declination of the North
Celestial Pole is +90°), with Declination south of the
celestial equator indicated with a "-" sign (e.g., the
Declination of the South Celestial Pole is -90°). Any point
on the celestial equator itself (which, for example, passes
through the constellations Orion, Virgo and Aquarius) is
specified as having a Declination of zero, shown as 0° 0' 0".
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- Right Ascension: The celestial analog to Earth longitude
is called "Right Ascension," or "R.A.," and is measured in
time on the 24 hour "clock" and shown in hours ("hr"),
minutes ("min") and seconds ("sec") from an arbitrarily
defined "zero" line of Right Ascension passing through the
constellation Pegasus. Right Ascension coordinates range
from 0hr 0min 0sec to 23hr 59min 59sec. Thus 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 prime Right Ascension grid line (0hr
0min 0sec) carry increasing R.A. coordinates.
All celestial objects are specified in position by their celestial
coordinates of Right Ascension and Declination. The
telescope's R.A. and Dec setting circles (7 and 8, Fig. 7) may
be dialed to the coordinates of a specific celestial object,
which may then be located without a visual search. However,
before you can make use of the telescope's setting circles to
locate celestial objects, your telescope must first be polar
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b. Polar Alignment
The Meade ETX can be used for astronomical observations in
the same way as just described for terrestrial observations:
simply set the telescope on a tabletop, locate objects through
the viewfinder, and then observe through the main telescope.
Objects can be tracked, or followed, as they move across the
sky by turning one or both of the R.A. and Dec Slow-Motion
Controls (10 and 16, Fig. 1). Such usage of the telescope,
however, is unnecessarily cumbersome, since, by attaching
the Table Tripod legs to the ETX and following a procedure
called Polar Alignment, the telescope can be made to track
objects completely automatically.
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 is not obvious to the unaided eye, but
viewed through a serious telescope such as the ETX, 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 15 to 60 seconds, depending on the
For easy tracking of astronomical objects the ETX should be
polar aligned, as follows:
1. Make sure the viewfinder is aligned with the ETX Astro
Telescope, as previously described in this manual.
2. Attach the three tripod legs to the drive base of the
telescope. (see Fig. 7) Two identical legs thread into the
side of the telescope's drive base (first remove the
threaded cover-buttons). The third leg, which includes a
scribed scale along its length, should be threaded into the
center hole of the drive base. The scribed scale reads
the latitude of the observing location. Threading in the
three legs to a firm feel is sufficient.
3. A small thumbscrew (4, Fig. 7) is attached to the center
tripod leg. Loosening this thumbscrew allows the outer
section of the leg to slide over the inner section, so that
the length of the leg can be extended. Extend the center
tripod leg so that the center of the thumbscrew-head is
lined up with the latitude of your location on the scale.
Then retighten the thumbscrew to a firm feel. Determine
the latitude of your observing location from a road map or
atlas, or call your local airport; determining your latitude
within about one degree is sufficient. The latitudes of major
cities throughout the world are listed later in this manual.
Example: The latitude of New York City is 41°. The center
tripod leg should be extended so that the center of the
thumbscrew is set next to the 41° reading on the scale.
Note: With the center tripod leg threaded fully into the
center hole of the drive base, the latitude scale may be at
an inconvenient position for reading the latitude scale
(e.g., the scale may be facing the drive base). This
situation can be remedied as follows:
- Remove the center tripod leg from the telescope's drive base.
- Unthread completely the small thumbscrew which locks the leg's inner section to its outer section.
- Rotate the inner tripod section 180 ° inside the outer section.
- Replace the thumbscrew which locks the inner section to the outer section.
- Replace the center leg in the drive base. The latitude scale will now be placed at an easily readable position.
4. Unlock the R.A. Lock and Dec Lock (11 and 21, Fig 1) and
rotate the telescope so that it is oriented as shown in Fig.
8. Re-lock the R.A. Lock and Dec Lock. In this orientation
the telescope's optical tube is lined up parallel to the
tripod's center leg.
5. Note the dotted line and arrow extending from the
telescope tube in Fig. 8. This line defines the telescope's
polar axis. Lift the entire telescope, including tripod, and
place the telescope on a tabletop so that this axis is
pointed due North. For example, if you know the location
of Polaris, the North Star, then point the telescope directly
at Polaris. (Fig. 9)
Fig. 7: The ETX ready for astronomical observing. (1) Fixed-
length tripod legs; (2) Scribed scale for reading latitude of
observing location; (3) Center tripod leg; (4) Thumbscrew
for locking extension of center leg; (5) Indicator arrow for
Dec. circle; (6) Indicator arrow for R.A. circle; (7) R.A.
Setting Circle; (8) Dec. Setting Circle.
Fig. 8: To polar align the ETX, place the telescope's optical tube parallel to the
center tripod leg, as shown. Then lift and orient the entire telescope until the
telescope's polar axis (dotted arrow) points due North.
Fig. 9: Locating Polaris
Note: Observers located in the Earth's southem
hemisphere (e.g., South America, Australia, etc.) should
point the telescope's polar axis due South.
6. From this point on, only move the telescope using the R.A.
and Dec controls. Any other movement of the telescope
will nullify the polar alignment procedure.
Polar alignment of the telescope thus requires two procedures:
extending the center tripod leg to the correct latitude position
and pointing the telescope's polar axis due North.
The center tripod leg has a latitude range of from 27.5° to
42.5°. Observers located at latitudes higher than 42.5° may
achieve equatorial alignment by placing the center tripod leg in
the upper hole position (2, Fig. 3). Polar alignment may in this
way be achieved to latitudes as high as 48°. Note, however,
that the latitude scale on the center tripod leg no longer is valid
when the leg is placed in the upper hole position. In this case
the center tripod leg should be extended until the telescope's
polar axis points to Polaris, or due North, an alignment obtained
by sighting along the telescope tube with the telescope
oriented as shown in Fig. 8.
If the observing location is at latitudes below 27.5°, the
telescope can be polar aligned by placing the center tripod leg
in the lower hole position (4, Fig. 3). Again, polar alignment can
be obtained by sighting along the telescope tube, per the
orientation in Fig. 8, and extending the center tripod leg so that
the telescope's polar axis points to Polaris. Polar alignment at
latitudes as low as 22° may be achieved in this way.
If your observing latitude is higher than 48°, the optional
High-Latitude Tripod Leg, is available and allows for polar alignment as high as
Important note: For almost all astronomical observing
requirements approximate settings of the telescope's latitude
and polar axis are acceptable! Do not allow undue attention to
precise polar alignment of the telescope interfere with your
basic enjoyment of the instrument.
[ toc ]
c. Alternate Polar Alignment Procedure
If desired, more precise polar alignment (particularly if your
latitude requires that you use the upper or lower hole
positions, (2 and 4, Fig. 3) for attachment of the center tripod
leg) may be obtained by first orienting the telescope as shown
in Fig. 8. Use the R.A. Slow-Motion Control (10, Fig. 1) to move
the telescope so that the eyepiece is positioned as shown in
Fig. 8. Then follow this procedure:
- Align the telescope's optical tube by your eye so that it is
parallel to the telescope's center tripod leg. Use the Dec
Slow-Motion Control (16, Fig. 1) to make the optical tube
and center tripod leg as nearly parallel to each other as
your eye can detect, as shown in Fig. 8.
- Lift the entire telescope, including tripod, and place it on
the observing table so that the telescope's polar axis
(dotted arrow in Fig. 8) is pointing due North.
- While observing through the SP 26mm eyepiece of the
main telescope, adjust the length of the center tripod leg
until Polaris is visible in the eyepiece. Do not use the R.A.
and Dec Slow-Motion Controls. Instead, 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 center tripod leg to place Polaris
in the center of the telescope's field.
Although the above procedure is somewhat tedious (since the
actual field of view of the main telescope with the SP 26mm
eyepiece in place is only about 1°), it is a worthwhile effort if
fairly 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 field, the telescope will be polar
aligned within about one or two degrees - a level of alignment
precision more than sufficient for almost any observing
To provide the most stable platform from which to polar align
your ETX Astro Telescope you may wish to purchase the ETX
Field Tripod (Fig. 5). The tripod head tilts easily to your local
latitude angle for quick polar alignment, and locks in a 90°
position to facilitate terrestrial viewing.
[ toc ]
d. Locating Astronomical Objects
Now that your telescope is fully assembled and polar aligned,
you are ready to begin observations.
For the beginning amateur astronomer, the simplest method of
locating objects in the night sky - and an excellent way to learn
how to operate your telescope - is to look at a celestial object
that can be clearly seen with your own eyes.
To move the telescope freely in R.A and Dec, first loosen both
the R.A. and Dec Locks (11 and 21, Fig. 1). Find the desired
object in the viewfinder, center the object in the viewfinder's
crosshairs, then observe through the main telescope's
eyepiece. Tighten the R.A. and Dec locks. Then, adjust the
focus knob until the image is clear and sharp.
The positions of celestial objects change over the course of
the year, so you should obtain a star chart (such as the
Meade Star Charts, available from your Meade dealer) or refer to the
monthly star charts presented in astronomy magazines, such
as Sky & Telescope and Astronomy.
Once the object is centered in the eyepiece, it is necessary to
slowly turn the R.A. Slow-Motion Control (10, Fig. 1) to keep
the object in the field of view. However, once the telescope is
polar aligned, the motor drive (described below) may be used
to automatically track on the object.
[ toc ]
e. The Motor Drive
The ETX Astro Telescope is driven by a DC electronic motor
control system, powered by three AA-size batteries located
inside the telescope's drive base (see GETTING STARTED).
To use the motor drive, follow this procedure:
- With the telescope polar aligned as described above, turn
the motor drive on, using the switch (8, Fig. 3) located on
the bottom of the drive base.
- Northen/Southern Hemisphere Operations: Observers
located in the Earth's northern hemisphere (e.g., North
America, Europe, Japan) should place the N-S switch (7,
Fig. 3) permanently in the "N" (north) position. Observers
in the Earth's southern hemisphere (e.g., Australia and
most of South America) should place this switch in the "S"
position, resulting in motor drive operation in the opposite
- After switching the motor drive on, allow one minute for
the drive to take up any internal gear-backlash. During this
initial one minute period, the motor drive is non-operative.
- Now, as you move the telescope from object to object, the
motor drive will automatically track, or follow, the object,
fully compensating for the effects of the Earth's rotation.
When each new object is centered in the telescope's
field, the R.A. Lock and Dec Lock should be locked; the
motor drive takes hold within a few seconds after the
R.A. Lock is locked.
[ toc ]
f. Setting Circles
The ETX is equipped with R.A. and Dec Setting Circles (15 and
18, Fig. 1). To aid the observer in the location of faint celestial
objects, setting circles emulate the celestial coordinates found
on star charts and in sky catalogs. Any charted object can be
easily located by their R.A. (in hours, minutes, and seconds,
from Oh 0m 0sec to 23h 59m 59sec) and Dec (from 0° to ±90°)
With the ETX telescope polar aligned, turning the R.A.
SlowMotion Control (10, Fig. 1) moves the telescope in Right
Ascension; turning the Dec Slow-Motion Control (16, Fig. 1)
moves the telescope in Declination.
The Dec setting circle has been factory set to read the correct
Declination of sky objects, but this setting should be
re-checked the first time the setting circles are used. With the
telescope polar aligned, point the telescope as shown in Fig. 8
and center the North Star, Polaris (Fig. 9), in the telescopic
field. Polaris has a Declination of 89.2°. With Polaris centered in
the field of view, both Dec setting circles should therefore read
89.2°, using the small indicator arrow (5, Fig. 7) located
immediately under each Declination circle. The Dec setting
circles can be moved by slightly unthreading their cover plates,
adjusting the circle positions, and then retightening the cover
Since celestial objects move in Right Ascension, the R.A.
setting circle must be set as each object is located during an
observing session. This point is explained in more detail below.
Note that 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 should be used by observers in the Earth's
northern hemisphere, the lower row by observers in the
Earth's southern hemisphere.
The indicator arrow (6, Fig. 7) for the R.A. setting circle is
located on the opposite side of the drive base from the
position where the two fixed table tripod legs attach and
immediately under the R.A. circle.
To use the setting circles, the ETX must first be polar aligned; it
is advisable that the motor drive be turned on and that a
lowpower eyepiece (e.g., the SP 26mm eyepiece) be
employed. Then follow this procedure:
Fig. 10: Manually turning the R.A. setting circle to read the Right Ascension of an object.
- 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
some bright stars are listed further on in this manual, or use a sky
catalog. Center this object in the telescope's field of view.
- Manually turn the R.A. circle (Fig. 10) to read the R.A. of the object.
- 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 as described above.
- Without touching the setting circles, move the telescope
(manually, by unlocking the R.A. and Dec Locks, or by
using the R.A. and Dec Slow-Motion Controls) so that the
setting circle indicators (5 and 6, Fig. 7) read the R.A. and
Dec coordinates of a second object that you wish to
- If the above procedure has been followed carefully, the second object will now be in the telescope's field of
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.
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 easy-to-find object. In this way the
precision required for accurate object location will become
[ toc ]
g. Photography Through the ETX Astro Telescope
Photography through the ETX Astro Telescope requires the
addition of the optional #64 T-Adapter (see OPTIONAL
ACCESSORIES, page 14). With the #64 T-Adapter attached to
the telescope (Fig. 11), through-the-telescope photography is
possible with any 35mm camera body with removable lens. In
this way the telescope effectively becomes the lens of the
For through-the-telescope photography, turn the Flip-Mirror
Control, (5, Fig. 11) to the "down" position, allowing light to
pass straight through the telescope and out the Photo Port (6,
Fig. 1). With the Flip-Mirror Control in the "down" position and
the Photo Port's dust cover removed, the front lens of the
telescope can be seen when looking through the Photo Port.
The #64 T-Adapter threads on to the Photo Port, followed by a
T-Mount for the particular brand of 35mm camera being used,
followed in turn by the camera body itself (with camera lens
Fig. 11: 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) 35mm camera body.
Note that the #64 T-Adapter consists of two sections (1 and 2,
Fig. 11) which are threaded together in shipment. Either of the
following photographic mounting formats may be used to
couple the camera body to the telescope's Photo Port thread.
Format 1: Camera Body + T-Mount + Section (1) of the #64
Format 1 utilizes the short section only of the #64 T-Adapter to
permit close-coupling of a camera body to the telescope at an
effective photographic speed of f/14 and a transmission value
(the so-called "T"-value) of 18. In this format vignetting will
occur: the photographic image will appear on film as a circle,
without illuminating the complete 35mm frame.
Format 2: Camera Body + T-Mount + Sections (1) and (2) of
the #64 T-Adapter.
Format 2 utilizes both sections of the #64 T-Adapter threaded
together to form a rigid unit as shown in Fig. 11, the telescope
is operating at a photographic speed of f/16 and T-value of 23,
but without any field vignetting: images are illuminated to the
edges of a standard 35mm frame.
To frame an object in the viewfinder of the 35mm camera body,
loosen slightly the knurled ring (3, Fig. 11) 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.
Photography through a long lens such as the ETX requires
special technique for good results, and the photographer
should probably expect to waste a roll or two of film in
acquiring this technique. Long-lens photography has its own
rewards, however; rewards that short-focus lenses can not
A few tips on photography through the ETX:
- Use a rigid tabletop or the optional Meade ETX Field Tripod
as a platform for the telescope. At effective focal lengths
of 1250mm to 1450mm, even small external vibrations can
easily ruin an otherwise good photo.
- Use a cable-operated shutter release. Touching the
camera body to initiate shutter operation will almost
certainly introduce undesirable vibrations.
- Focus the image with extreme care. While observing the
subject through the camera's reflex viewfinder, turn the
ETX's focus knob (5, Fig. 1) to achieve the sharpest
- Correct shutter speeds vary widely, depending on lighting
conditions and the film used. Trial-and-error is the best
way to determine proper shutter speed in any given
- Terrestrial photography through the ETX 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
- Photography of the Moon and planets through the ETX
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
and that the telescope's motor drive be in operation.
Note that long-exposure photography of deep-space objects
is not practical with the ETX, since this type of photography
requires special electronic and optical guiding devices not
available for this telescope.
[ toc ]
h. Objects In Space
Listed below are just some of the many astronomical objects
that can be seen with your ETX Astro Telescope:
[ toc ]
1. The Moon
The Moon is, on average, a distance of 230,000 miles
(370,000km) from Earth and is the easiest object to view
at night. It is best observed during its crescent or half
phase, when sunlight strikes its surface at an angle,
casting shadows and adding a sense of depth to your
view. No shadows are seen during a full Moon, causing
the overly bright Moon to appear flat. Using your new
ETX Astro Telescope, you can see brilliant detail on the
Moon, including many hundreds of lunar craters and
maria, described below:
Craters are round meteor impact sites covering most of
the Moon's surface. With no atmosphere on the Moon, no
weather conditions exist to erode the craters. Thus, lunar
craters can last for millions of years.
Maria (plural for mare) are smooth, dark areas scattered
across the lunar surface. These dark areas are thought
to be ancient impact craters that were filled with lava
from the interior of the Moon.
In the late 1960's and early 1970's, a total of 12 Apollo
astronauts left their footprints on the Moon. However, no
telescope on Earth is able to see these footprints. In fact,
the smallest lunar feature that can be seen with the
largest telescope on Earth is about half a mile across.
Note: Except during its early crescent phase, the Moon
can be an exceptionally bright object to view through
your telescope. To reduce the brightness and glare the optional #905
Variable Polarizing Filter is recommemded.
[ toc ]
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 Astro 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 its thick cloud cover.
Mars is about half the diameter of Earth. Mars appears
as a tiny reddish-orange dot. It may be possible to see a
hint of white at one of the planet's polar ice caps. When
Mars is closest to Earth, additional detail on the planet's
surface may be visible.
Jupiter is 11 times the diameter of Earth. This large
planet appears as a disk with several dark lines
stretching across its surface. These dark lines are cloud
bands in Jupiter's atmosphere. Four of Jupiter's 16 moons
(lo, Europa, Ganymede, and Callisto) can be seen as
"star-like" points of light. Just as Earth's Moon travels
around Earth, Jupiter's moons circle around Jupiter. As a
result, the number of moons visible at any given time
changes as they orbit in front of, or behind, the giant
Jupiter is the largest planet in the Solar System. While
Jupiter's disk may look small through the telescope, keep
in mind that over 1000 Earths could fit inside the planet.
Saturn 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, didn't understand what the rings
were and believed instead that Saturn had "ears."
Saturn's rings are made of billions of ice particles ranging
in size from a speck of dust to the size of a house. The
major division in Saturn's rings, called the Cassini Division,
is generally visible through the ETX. Titan, the largest of
Saturn's 18 moons can also be seen through the ETX as a
bright, starlike object near the planet.
[ toc ]
3. Deep-Sky Objects
Beyond Our Solar System,
star charts can be used to locate constellations, individual
stars and deep-sky objects. Examples of various
deep-sky objects are given below:
Stars are large globes of incandescent gases. Because
of their vast distances from our Solar System, all stars
appear as pinpoints of light, irrespective of the size of the
Diffuse Nebulae are clouds of dust and gas where
stars are formed. The Great Nebula in Orion (M42) is a
diffuse nebula that appears as a faint wispy gray cloud.
M42 is 1600 light years in distance from Earth.
Galaxies are large groupings of stars, nebulae, clusters,
and more. The most common shape is spiral, but galaxies
also are elliptically-shaped, or even seen as irregular
blobs. The Andromeda Galaxy (M31) is the closest
spiral-type galaxy to the Milky Way. This galaxy appears
faint, fuzzy, and cigar-shaped, is 2.2 million light years
away and is a fascinating object to see through the ETX.
Open Clusters are loose groupings of young stars, all
recently formed from the same diffuse nebula. The
Pleiades (M45) in Taurus is an open cluster. M45 is 410
light years away. Through the ETX several hundred stars
are visible in the Pleiades.
Constellations are large, imaginary groupings of stars
and are too large to be seen through a telescope To learn
the constellations, start with an easy grouping of stars,
like the Big Dipper in Ursa Major. Then, use a star chart to
find your way from there.
[ toc ]
3. Helpful Charts
[ toc ]
a. Latitudes of the World
To aid in the polar alignment procedure, previously described in this manual, 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.
Northern hemisphere observers (N): If your site is over
70 miles (110 km) north of the listed city, add one degree for
every 70 miles. If your site is over 70 miles south of the listed
city, subtract one degree per 70 miles.
Southern hemisphere observers (S): If your site is over
70 miles north of the listed city, subtract one degree for every
70 miles. If your site is over 70 miles south of the listed city,
add one degree per 70 miles.
|Albuquerque||New Mexico||35° N|
|Atlanta|| Georgia||34° N|
|Boston|| Massachusetts||42° N|
|Chicago|| Illinois||42° N|
|Kansas City||Missour||39° N|
|Las Vegas||Nevada||36° N|
|Little Rock||Arkansas||35° N|
|Los Angeles||California||34° N|
|Milwaukee ||Wisconsin||46° N|
|New Orleans||Louisiana||30° N|
|New York||Now York||41° N|
|Oklahoma City||Oklahoma||35° N|
|Salt Lake||City Utah||41° N|
|San Antonio||Texas||29° N|
|San Diego||California||33° N|
|San Francisco||California||38° N|
|Washington||District of Columbia||39° N|
|Glasgow ||Scotland||56° N|
|Lisbon ||Portugal||39° N|
|Buenos Aires||Argentina||35° S|
|Seoul ||South Korea||37° N|
|Victoria||Hong Kong||23° N|
|Cape Town||South Africa||34° S|
|Adelaide||South Australia||35° S|
|Canberra||New South Wales||35° S|
|Alice Springs||Northern Territory||24° S|
|Perth||Western Australia||32° S|
|Sydney||New South Wales||34° S|
[ toc ]
1b. Star Locator
Following are a list of bright stars and their R.A. and Dec
coordinates. Once your telescope is polar aligned, use the
R.A. and Dec setting circles to explore the sky.
|Fall||Fomalhaut||Piscis Austrinis||22h58m||-29° 38"|
|Winter||Sirius Canis||Major||06h45m||-16° 43"|
[ toc ]
TELESCOPE MAINTENANCE AND SERVICING
[ toc ]
1. General Maintenance
The ETX Telescope is a precision optical instrument designed
to yield a lifetime of rewarding applications. Given the care
and respect due any precision instrument, the ETX will rarely,
if ever, require factory servicing or maintenance. Maintenance
- 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.
- When absolutely necessary, dust on the front lens should
be removed with gentle strokes of a camel hair brush or
blown off with an ear syringe (available at any pharmacy).
- Organic materials (e.g., fingerprints) on the front lens may
be removed with a solution of 3 parts distilled water to 1
part isopropyl alcohol. You may also add 1 drop of
biodegradable dishwashing soap per pint of soluton. Use
soft, white facial tissues and make short, gentle strokes.
Change tissues often.
CAUTION: Do not use scented or lotioned tissues
or damage could result to the optics
- 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 is mounted in this cell. The lens cleaner solution
described in Step c. may be used to clean the inside
surface of the lens. DO NOT use a commercial
photographic lens cleaner
CAUTION: Do not touch the aluminized circular
surface of the secondary mirror with your finger,
a tissue, or any other object. Scratching of the
mirror surface will otherwise almost certainly
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 else optical alignment of the lens will be lost,
necessitating a return of the telescope to the Meade
- If the ETX is used outdoors on a humid night, water
condensation on the telescope surfaces will probably
result. 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
the telescope is packed away. Do not, however, wipe
any of the optical surfaces. Rather, simply allow the
telescope to sit for some time in the warm indoor air, so
that the wet optical surfaces can dry unattended.
- If the ETX Telescope is not to be used for an extended
period, perhaps for one month or more, it is advisable to
remove the three AA-batteries from inside the drive base.
Batteries left in the circuit board for prolonged periods
may leak, causing damage to the telescope's electronic
- The super-gloss anodized finish of the ETX's deep-violet
optical tube will fade if left in direct sunlight for prolonged
- Do not leave the ETX telescope inside a sealed car on a
warm summer day; excessive ambient temperatures can
damage the telescope's internal lubrication and electronic
A set of three (English-format) hex wrenches is provided
with each ETX Astro Telescope. These wrenches are
used as follows:
Small wrench (.050"): Use the small wrench to tighten
the set-screws of any knobs which may loosen (e.g., the
Dec Slow-Motion Control knob, Focus knob, R.A. Lock,
R.A. Slow-Motion Control knob, or Flip-Mirror Control
Medium wrench (1/16"): This wrench is used to detach
the viewfinder bracket from the telescope's rear-cell.
Large wrench (7/64"): The large wrench is used to detach the ETX
optical tube assembly from its fork mount, permitting
placement of the tube assembly on a standard photo
[ toc ]
2. Storage and Transport
When not in use, store the telescope 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. 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.
[ toc ]
3. Inspecting the Optics: A Note About the "Flashlight" Test:
If a flashlight or other
highintensity 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 appears to be
scratches, dark or bright spots, or just generally 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
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.
[ toc ]
The following suggestions may be helpful if you are having
difficulty observing objects through the ETX Astro Telescope:
- Confirm that all the lens covers have been removed from
- Confirm that the Flip-Mirror Control (7, Fig. 1) is in the "up"
position if using the Eyepiece Holder (4, Fig. 1) so light is
directed to the eyepiece (1, Fig. 1). Confirm that the
FlipMirror Control is in the "down" position if using the
#932 Erecting Prism or doing photography with the ETX.
- If you are new to stargazing, first locate and focus on
bright objects, such as the Moon, or a bright star or
planet, to acquaint yourself with the sky.
- When objects appear in the viewfinder but not in the
telescope, the viewfinder is not properly aligned with the
telescope. Before the ETX is used the first time, the
viewfinder must be aligned to the main telescope.
Once aligned, locate objects in the viewfinder first,
then move to the main telescope.
- Air conditions inside a warm house or building may distort
terrestrial or celestial images and make 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.
- For clear viewing of objects, turn the focus knob (5, Fig. 1)
slowly since the "in-focus" point of a telescope is precise.
- The optics within your telescope need time to adjust to the
outside ambient temperature to provide the sharpest
image. To "cool down" the optics, set your telescope
outside for 10 to 15 minutes before you begin observing.
[ toc ]
5. Meade Customer Service
If you have a question concerning your ETX telescope, call
Meade Instruments Customer Service Department at
(949) 451-1450, or fax at (949) 451-1460. Customer Service hours are
8:30AM to 4:30PM, Pacific Time, Monday through Friday. In the
unlikely event that your ETX requires factory servicing or
repairs, write or call the Meade Customer Service
Department first, before returning the telescope to
the factory, giving full details 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
[ toc ]
|Optical Design||Maksutov-Cassegrain catadioptric|
|Primary Mirror Diameter||96mm (3.78")|
|Clear Aperture||90mm (3.5")|
|Focal Ratio (photographic speed)||f/1 3.8|
|Near Focus (approx.)||11.5 ft. (3.5m)|
|Resolving Power (arc sees.)||1.3|
|Super Multi-Coatings (EMC)||Standard|
|Limiting Visual Steller Magnitude (approx.)||11.7|
|Maximum Practical Visual Power||325X|
|Optical Tube Dimensions (dia. x length)||4. 1" x 11" (1 0.4cm x 27.9cm)|
|Secondary Mirror Obstruction (dia.; %)||1.1" (27.9mm); 9.6%|
|Telescope Mounting||Fork type; double tine|
|Setting Circle Diameters||Dec: 3.5"; R.A.: 7"|
|RA Motor Drive System||4.5-volts DC|
|Hemispheres of Operation||North and South, switchable|
|Slow-Motion Controls||Manual, R.A. and Dec|
|Bearings||R.A. and Dec.: Nylon|
|Materials: Tube body||Aluminum|
| Mounting||High-impact ABS, steel reinforced|
| Primary Mirror||Pyrex® glass|
| Correcting Lens||BK7 optical glass, Grade-A|
|Telescope Dimensions||15" x 7.3" x 8.5" (38cm x 18.5cm x 21.6cm)|
|Telescope (Incl. tabletop tripod) Net Weight||9.2 lbs. (4.2 kg)|
|Telescope Shipping Weight||12.4 lbs. (5.6kg)|