Meade 102ACHR/500 User manual

INSTRUCTION MANUAL
Meade* Model 102ACHR/500
4" Achromatic Refracting Telescope
Meade Instruments Corporation
ii*

WARNING!
Never use the Meade Model 102ACHR/500 Telescope to look at the Sun ! Observing the Sun, even
for the shortest fraction of a second, will cause instant and irreversible damage to your eye as
well as physical damage to the telescope itself. When observing with the telescope during the
daytime, do not point the telescope even close to the Sun.
Fig. 1: The Meade Model 102ACHR/500 Refracting Telescope

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Captions for Fig. 1
1. Cradle Rings
2. Viewfinder
3. Focuser Lock Knob
4. Eyepiece
5. Diagonal Prism
6. Focus Knob
7. Declination (Dec) Slow Motion Control
8. Right Ascension (R.A.) Setting Circle
9. Dust Cover for Optional #812 Polar Alignment
Finder
10. Latitude Scale
11. Fine Latitude Adjustment Knob
12. Tripod Legs
13. Tripod Head
14. Fine Azimuth Adjustment Knob
15. Counterweight Safety Stop
16. Counterweight Rod
17. 7.5 lb (3.4 kg) Counterweights
18. Counterweight Cone
19. Polar Axis
20. Dec Setting Circle
21. Dec Lock Lever
22. Cradle Ring Knobs
23. Objective Lens Cell
24. Dew Shield Safety Screw
25. Dew Shield
26. Latitude Angle (Elevation Angle) of the
Polar-Aligned Telescope
27. Declination Axis
28. Counterweight Lock Screws
29. Cradle Ring Lock Knobs
CAUTION!
The Meade Model 102ACHR/500 telescope is a
serious astronomical instrument. Because of the
significant weight of the telescope, children should
not be allowed to play near the telescope at any time.
Parents should use caution and common sense when
allowing children to observe through the telescope.
Technical Note: The Model 102ACHR/500 may be supplied in
either of two versions: with either the Meade LXD 500A
Equatorial Mount (with aluminum gears) or the LXD 500B
Equatorial Mount (with bronze gears). Set up and operation of
the telescope are identical in either case.
® The name 'Meade' and the Meade logo are trademarks
registered with the U.S. Patent Office and in principal
countries throughout the world.
Contents
Model 102ACHR/500
4" Achromatic Refractor
Introduction.4
Parts Listing and Assembly.4
Preparing the LXD 500 Tripod.4
Setting Up the tripod.4
Attaching the Accessory Tray.4
Varying the Tripod Height.4
Collapsing the Tripod.4
Assembly of the Equatorial Mount.4
Attaching the Equatorial Head to the Tripod.5
Attaching the Counterweights.5
Slow Motion Control Knobs.5
Mounting the Cradle Rings.5
Mounting the Optical Tube Assembly.6
Attaching the Diagonal Prism and Eyepiece.6
Mounting the Viewfinder.6
Balancing the Telescope. 6
First Observations.7
Telescope Controls 7
The Viewfinder.7
Focusing the Viewfinder.7
Alignment of the Viewfinder.7
Using the Viewfinder.8
Magnification.8
Astronomical Observing.8
Celestial Coordinates: Declination & Right Ascension . . 8
Polar Alignment.9
Polar Alignment Procedures.9
Using a Polar Aligned Telescope.10
Locating Astronomical Objects.10
Precise Polar Alignment Procedures.10
Setting Circles.10
Observing Tips.10
Terrestrial Observing.11
image Orientation.11
Optional Accessories.11
Telescope Maintenance and Servicing.12
General Maintenance Guidelines.12
Proper Storage and Transport of the Telescope.13
Meade Customer Service.13
Specifications.14
1998 Meade Instruments Corporation

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MODEL 102ACHR/500
4" ACHROMATIC REFRACTOR:
INTRODUCTION
The Meade Model 102ACHR/500 Telescope is ideally suited to
the serious beginning or intermediate amateur astronomer or
terrestrial observer. With its 2-element, 4" achromatic objective
lens, observers can view craters and fault lines on the Moon;
cloud features on the planet Jupiter and Jupiter's four largest
moons, as well as the rings of Saturn and Saturn’s largest
moon. Titan, Beyond the Solar System, the Model
102ACHR/500 telescope permits detailed observations of
nebulae, star clusters, galaxies, and other deep-space objects.
For optimal enjoyment of the Meade Model 102ACHR/500
telescope, please take a few minutes to read this manual
thoroughly and become familiar with all of the instrument's
astronomical and terrestrial observing capabilities.
PARTS LISTING AND ASSEMBLY
When opening the two packing boxes for the first time, note
carefully the following parts included with the Model
102ACHR/500 telescope:
Box 1:
■ Optical Tube Assembly, with-cradle rings attached.
■ Accessories, packed with the optical tube assembly:
— Plossl (PL) 25mm eyepiece
— #918A diagonal prism
- 6 x 30mm viewfinder and bracket
r-ig. 2 XT- 100 Tripod. (1) Azimuth Tangent Arm; (2) Tripod Head;
i * -nmon strut: (4) Accessory Tray; (5) Height Adjustment
Box 2:
■ LXD 500 Equatorial Mount, including:
— Tripod
— Equatorial head
— Lock knob with twist bar (Fig. 4)
— 2 washers (1 large and 1 small washer for lock knob
with twist bar)
— Counterweight rod with gray counterweight cone
— 2 pcs. 7.5 lb (3.4 kg) counterweights
— 2 slow motion control knobs
— Accessory tray
To assemble the telescope, follow these steps:
1. Preparing the LXD 500 tripod
The LXD 500 tripod (Fig. 2) is shipped virtually completely
assembled from the factory. Once set up, all that is required of
an observer is to attach the accessory tray and adjust the tripod
to the desired observing height.
a. Setting Up the Tripod:
Remove the tripod from the shipping box and stand the
tripod vertically with the tripod feet down. Grasp two of the
tripod legs and with the full weight of the tripod on the third
leg, gently pull the legs apart to the fully open position
(Fig. 2).
b. Attaching the Accessory Tray:
Remove the round accessory tray (4), Fig. 2. from the
shipping box.
Unthread the black, star-shaped lock knob from the bottom
of the tray.
Place the threaded rod on the underside of the accessory
tray through the central hub of the extension strut.
Rethread the lock knob onto the accessory tray.
c. Varying the Tripod Height:
Loosen the black, star-shaped height adjustment knob (5),
Fig. 2, at the base of each tripod leg.
Slide the three inner tripod leg sections out to the desired
height.
Firmly tighten (but do not overtighten) the three height
adjustment knobs (5), Fig. 2.
d. Collapsing the Tripod:
Remove the accessory tray (4), Fig. 2. Grasp the tripod
head (2), Fig. 2, with one hand. With the other hand, pull
directly up on the central hub of the extension strut, where
the accessory tray (4), Fig, 2, was attached. This action
will cause the tripod legs to move inward to a collapsed
position.
Important Notes on the LXD 500 Tripod:
• Remove the accessory tray before attempting to collapse
the tripod.
• If the tripod does not extend or collapse easily, do not
force the tripod legs in or out. By following the above
instructions, the tripod will function properly. Forcing the
tripod into an incorrect position may damage the extension
strut system.
• Do not overtighten the three star-shaped height adjustment
knobs on the tripod legs. “Firm feel” tightening is sufficient.
2. Assembly of the Equatorial Mount
All the parts required for the Equatorial Mount can be found
(with the tripod) in the LXD 500 Mount shipping box. The
Optical Tube Assembly (OTA) is shipped in a separate box. To
assemble the mount, follow these instructions:

Fig. 3: Attaching the Equatorial Head to Tripod. (1) Fine Azimuth
Adjustment Knobs; (2) Azimuth Tangent Arm; (3) North Facing Tripod
Leg; (4) Tripod Head; (5) Equatorial Head.
a. Attaching the Equatorial Head to the Tripod:
On the Equatorial Head (5), Fig. 3, loosen the two Fine
Azimuth Adjustment Knobs (1), Fig. 3, to create a space
between the two knobs (as seen from the underside of the
Equatorial Head). The Azimuth Tangent Arm (2), Fig. 3, fits
between these two threaded knobs.
Unthread and remove the lock knob with twist bar, Fig. 4,
and two washers from the base of the Equatorial Head (5),
Fig. 3. Place the
Equatorial Head on the
Tripod Head (4), Fig. 3,
aligning it so that the
Azimuth Tangent Arm (2),
Fig. 3, slips between the
two Fine Azimuth
Adjustment Knobs (1),
Fig. 3.
With the Equatorial Head
(5), Fig. 3, sitting flat on
the Tripod Head (4), Fig. 3, place the small washer, then
the large washer over the threads of the lock knob with
twist bar, Fig. 4, and, from the underside of the Tripod
Head, thread the lock knob with twist bar (and washers)
through the Tripod Head and into the base of the Equatorial
Head. Tighten firmly but do not overtighten.
Simultaneously tighten both of the Fine Azimuth
Adjustment Knobs (1). Fig. 3. Each knob will press against
the Azimuth Tangent Arm (2), Fig. 3. Do not overtighten.
b Attaching the Counterweights:
On the counterweight rod (3), Fig. 5, confirm that the gray
counterweight cone (2), Fig. 5, is threaded onto the rod as
far as possible. Then, thread the counterweight rod, with
the counterweight cone in place, into the bottom of the
decimation housing (1), Fig. 5. When the counterweight
Fig. 5: Installing Counterweight Rod. (1) Declination Housing; (2)
Counterweight Cone; (3) Counterweight Rod; (4) R.A. Slow Motion
Control Shaft; (5) R.A. Lock Lever; (6) Dec Slow-Motion Control
Shaft (on opposite side); (7) Saddle Plate.
rod is threaded in as far as possible, additionally secure the
rod by turning the gray counterweight cone (2), Fig. 5,
clockwise until tight.
At the end of the counterweight rod (3), Fig. 5, unscrew the
counterweight safety stop (15), Fig. 1. Slide each
counterweight onto the rod and lock in place by tightening
its black counterweight lock screw (28), Fig. 1. As soon as
the second counterweight is secure, replace the
counterweight safety stop. Be certain that the
counterweight safety stop is always securely in place.
c. Slow Motion Control Knobs:
There are two identical slow motion control knobs. See (2)
and (4), Fig. 7. Attach one of these knobs to the R.A. Slow
Motion Control Shaft (4), Fig. 5, by aligning the knob so
that its knurled thumb screw will slide directly over the flat
area on the R.A. Slow Motion Control Shaft. Tighten the
knurled thumb screw to a firm feel. Do not overtighten.
Attach the second knob to the Dec Slow Motion Control
Shaft (6), Fig. 5, by aligning the knob so that its knurled
thumb screw will slide directly over the flat area on the Dec
Slow Motion Control Shaft. Tighten the knurled thumb
screw to a firm feel. Do not overtighten.
d. Mounting the Cradle Rings:
The Optical Tube Assembly .(OTA) is shipped from the
factory with the cradle rings (1), Fig. 1, secure around the
tube. To remove the cradle rings from the OTA, loosen
each cradle ring knob (22), Fig. 1. The cradle rings are
hinged so they can be opened by lifting the top portion of
the ring.
Unthread and remove the cradle ring lock knob (29), Fig. 1,
found at the base of each cradle ring (1), Fig. 1. Align the
base of each cradle ring with a mounting hole on the
saddle plate (7). Fig. 5, and thread a lock knob up through
the saddle plate into each cradle ring. Tighten to a firm
feel.

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Note: The cradle rings may be attached with the cradle
ring knobs on either the left or right side of the equatorial
head, as long as both hinges open in the same direction.
e. M ounting the Optical Tube Assembly:
Before placing the OTA in the cradle ring assembly, confirm that
the counterweights are attached to the mount and the R.A. lock
lever (3), Fig. 7, and the Dec lock lever (1), Fig. 7, are firmly
locked by rotating each lever clockwise until it stops.
With both cradle rings open, place the OTA into the cradle ring
assembly. With one hand holding the OTA in place, close the
cradle rings. Tighten the two cradle ring knobs to a firm feel. Do
not overtighten.
Located at the end of the OTA is the Dew Shield (25), Fig. 1,
which can be removed when .cleaning the objective lens (See
General Maintenance Guidelines, page 12.) Care should be
taken when replacing the Dew Shield to tighten the Dew Shield
Safety Screw (24), Fig. 1. Tightening of the safety screw will
prevent accidental dislodgment of the Dew Shield during an
observing session
Fig. 6: Attaching the Diagonal Prism and Eyepiece. (1) Alignment
Screws; (2) Viewfinder; (3) Focus Lock Knob; (4) Eyepiece:
(5) Diagonal Prism; (6) Focuser Drawtube; (7) Focus Knob;
(8) Viewfinder Mount
f. A ttaching the Diagonal Prism and Eyepiece:
Slide the diagonal prism (5), Fig. 6, directly into the focuser
drawtube (6) Fig. 6, of the telescope and lock in place by
turning its thumbscrew clockwise until tight (firm-feel only).
Insert the provided PL 25mm eyepiece (4), Fig. 6, into the
diagonal prism and lock in place by tightening the thumbscrew.
Do not overtighten the thumbscrews.
Note For astronomical observations, the diagonal prism
generally provides a comfortable right-angle viewing position.
Alternately . an eyepiece may be inserted directly into the rear
ceii for straight-through observations. With the diagonal prism
in place, images will be right-side-up but reversed left-for-right.
With the eyepiece inserted directly into the rear cell (straight
through), images will be upside-down. For astronomical
purposes, the image orientation is usually of no importance. For
■ errestnal observations, where a fully corrected image is highly
desiraole. the optional Meade #928 45° Erect-Image Diagonal
Pnsni should be ordered separately. (See Optional
Accessories, page 12.)
g. M ounting the Viewfinder;
The viewfinder, bracket and mounting hardware are shipped in
the box with the optical tube assembly.
Between the focus lock knob (3), Fig. 6, and the optical tube,
locate the four machine screws, Fig 6A, threaded into holes on
the flat, viewfinder mounting area.
Remove the four machine screws. Align the two holes and the
two open slots on the base of the viewfinder mount (8). Fig. 6,
with the threaded holes on the viewfinder mounting area.
Thread the four screws through the viewfinder mount into the
telescope. Tighten to a firm feel, but do not overtighten.
Alignment of the viewfinder is discussed later in this manual.
BALANCING THE TELESCOPE
The telescope must be balanced around both axes. With an
improperly balanced telescope, objects may become difficult to
find or, once found, may be easily lost. To balance the
telescope:
1. Loosen the R.A. lock lever (3), Fig. 7, by rotating the lever
counterclockwise until it stops. The Optical Tube Assembly
now rotates freely about the Polar Axis (19), Fig. 1. Rotate
the telescope so that the counterweight rod is parallel to
the ground (horizontal).
2. Loosen the counterweight lock screws (28), Fig. 1, and
slide the counterweights along the rod until the telescope
remains in one position without tending to drift in either
direction. Re-tighten the counterweight lock screws and
the R.A. lock lever.
3. Loosen the Dec lock lever (1), Fig. 7, by rotating the lever
counterclockwise until it stops. The Optical Tube Assembly
now rotates freely about the Declination Axis (27), Fig, 1.
Rotate the optical tube assembly so that the tube is parallel
to the ground (horizontal).
4. Slightly loosen the two cradle ring knobs (22), Fig. 1.
5. Slide the tube back and forth within the cradle rings until
the telescope is in balance about the Declination Axis.
Tighten the cradle ring knobs and the Dec lock lever when
balanced.
With the telescope properly balanced, it is possible to place the
optical tube in any position without drifting. Rebalancing may be
necessary with the addition of any optional accessories.
Fig. 7: Telescope Controls. (1) Dec Lock Lever; (2) R.A. Slow-
Motion Control; (3) R.A. Lock Lever; (4) Dec Slow-Motion Control.

Fig. 8: Viewfinder. (1) Viewfinder Eyepiece; (2) Rear Alignment
Screws; (3) Mounting Bracket; (4) Front Alignment Screws; (5) Focus
Lock Ring; (6) Objective Lens Cell.
FIRST OBSERVATIONS
Remove the dust cover from the objective lens by gently twisting
the cover and pulling It away from the objective lens.
Telescope Controls
An important array of controls facilitates operation of the Model
102ACHR/500 telescope. It is best to become familiar with all
of these controls before attempting observations through the
telescope.
Focus Knobs (7), Fig. 6: Turning these knobs moves the
eyepiece closer to or farther away from the objective lens,
thereby changing the focus. The telescope can be focused on
objects from a distance of about 50 feet to infinity.
Focus Lock Knob (3), Fig. 6: The focus lock knob is designed
to prevent the focuser drawtube (6), Fig. 6, from moving when
heavy accessories (e.g., a camera body) are attached to the
focuser assembly. For normal observing, with an eyepiece and
diagonal mirror, it is not necessary to utilize the lock knob.
Dec Lock Lever (1), Fig. 7: Locking and unlocking the
Declination movement of the optical tube is accomplished by
moving the Dec lock lever clockwise until it stops for the fully
locked position, or by moving the Dec lock lever
counterclockwise to the fully unlocked position.
Dec Slow-Motion Control (4), Fig. 7: With the Dec lock lever in
the fully locked position, the Dec Slow-Motion Control may be
used for fine motions of the telescope in Declination. (The
meaning of ''Dec," or Declination, is explained later in the
manual.)
R.A. Lock Lever (3), Fig. 7: Locking and unlocking the Right
Ascension movement is accomplished by rotating the R.A. lock
lever clockwise until it stops for the fully locked position and
counterclockwise for the fully unlocked position.
R.A. Slow-Motion Control (2), Fig. 7: With the R.A. lock lever
fully locked, the R.A. Slow-Motion Control permits manual slow-
motion of the telescope in Right Ascension. (The meaning of
"R.A.,” or Right Ascension, is explained later in the manual.)
After becoming familiar with the telescope’s controls, make your
first observations of a simple land object — a telephone pole or
building, perhaps, several hundred yards in the distance. Keep
in mind that the viewfinder has not been aligned, so it will be
necessary to sight along the optical tube to “aim" the telescope
at the object. With the PL 25mm eyepiece in place, unlock the
R.A, and Dec lock levers. The telescope now turns freely on
both axes, permitting the location of objects in the telescope.
With an object roughly centered in the telescopic field, as
viewed through the eyepiece, retighten the R.A. and Dec lock
levers. While looking through the eyepiece, turn the focus knob
clockwise or counterclockwise until the object is in focus.
Note: With the eyepiece inserted directly into the rear cell of the
telescope, without using the diagonal prism, the image through
the eyepiece will be inverted and reversed left-for-right. The
inverted image is a result of the optical structure of the telescope
and is normal for astronomical telescopes. If the diagonal prism
is inserted into the telescope first, then the eyepiece, the image
appears right-side-up, but still reversed left-for-right.
Once the selected object is in focus, with the R.A. lock lever and
Dec lock lever LOCKED, use the R.A. Slow-Motion Control and
the Dec Slow-Motion Control to center the object in the field of
view,
THE VIEWFINDER
The Model 102ACHR/500 telescope, 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. The viewfinder, by contrast, is
a low-power, wide-field sighting scope with crosshairs that
enable the easy centering of objects in the main telescope’s
field of view. Standard equipment with the Model 102ACHR/500
telescope is a viewfinder of 6-power and 30mm aperture, called
a “6 x 30mm viewfinder.”.
1. Focusing the Viewfinder
The viewfinder has been factory prefocused to objects located
at infinity. Individual eye variations, however, may require that
the viewfinder be refocused to your eye. Looking through the
viewfinder, point the telescope at a distant object; if the
viewfinder image is not sufficiently in focus for your eye, it may
be refocused as follows:
a. Remove the viewfinder from its mounting bracket (3),
Fig. 8, by slightly unthreading the six alignment screws (2)
and (4), Fig. 8, until the viewfinder can slip out easily.
b. Loosen the focus lock ring (5), Fig, 8. thereby enabling
rotation of the viewfinder's objective lens cell (6), Fig. 8.
While looking at a distant object through the viewfinder,
rotate the objective lens cell clockwise or counterclockwise
until sharp focus is achieved.
c. Tighten the focus lock ring (5), Fig. 8, to lock the focus in
place.
d. Replace the viewfinder into its bracket (3), Fig. 8, on the
main telescope.
Note: No focusing is possible (or required) from the eyepiece
end of the viewfinder.
2. 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:
a. The viewfinder bracket includes six alignment screws.
Turn the three rear alignment screws (2). Fig, 8, roughly
centering the viewfinder within its bracket (as viewed from
the eyepiece-end of the telescope). When centered,
tighten the knurled lock nut on each of the three rear
alignment screws until the lock nuts are flush against the
bracket ring.
b. Using the standard equipment PL 25mm eyepiece, point
the main telescope at some easy-to-locate, well-defined.

8
but distant, land object, such as the top ot a telephone
pole. Center the object precisely in the main telescope s
field and lock the R.A. lock lever and Dec lock lever so that
the telescope does not move away from the object.
c. While looking through the viewfinder, turn one or more of
the three front viewfinder alignment screws (4), Fig. 8. until
the crosshairs of the viewfinder point at precisely the same
position as the main telescope. Tighten the knurled lock
nut on each of the front alignment screws until the lock nuts
are flush against the bracket ring.
The viewfinder is now aligned with the main telescope. Unless
the alignment screws are disturbed, the viewfinder will remain
aligned indefinitely.
3. Using the Viewfinder
Now, to locate any object, terrestrial or astronomical, first center
the object on the crosshairs of the viewfinder; the object will then
be centered in the field of the main telescope.
Note: If higher observing magnifications are desired, first
locate, center, and focus the object using a low-power eyepiece
(e.g.. the PL 25mm eyepiece). Objects are easier to locate and
center at low powers: higher powers may then be employed by
changing eyepieces.
MAGNIFICATION
The magnification, or power, at which a telescope is operating is
determined by two factors: the focal length of the eyepiece
employed and the focal length of the telescope. The Model
102ACHR/500 telescope is supplied with one eyepiece as
standard equipment. The focal length of the eyepiece, 25mm,
is printed on its side.
Telescope focal length is, roughly speaking, the distance that
light travels inside the telescope before reaching a focus. The
focal length of the Model 102ACHR/500 telescope is 920mm
On a given telescope, different eyepiece focal lengths are used
to achieve different magnifications, from low to high. Optional
eyepieces and the Series 4000 #140 2x Barlow Lens are
available for powers from a range of about 25x to 400x.
depending on the focal length of the telescope and eyepiece
(see OPTIONAL ACCESSORIES, page 11).
To calculate the magnification (or power) obtained with a given
eyepiece, use this formula:
Telescope Focal Lengthy
Power - Ey e pj ece Focal Length
Example: Using the PL 25mm eyepiece supplied with the Model
102ACHR/500 telescope, the power is:
Power
920mm
25mm
= 37x
ASTRONOMICAL OBSERVING
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 tracking celestial objects.
Celestial Coordinates:
Declination and Right Ascension
Celestial objects are mapped according to a coordinate system
on the Celestial Sphere, the imaginary sphere 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. The faint star Sigma Octans lies near the South
Celestial Pole, where the extension of Earth's axis through the
South Pole intersects the 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.
In mapping the celestial sphere, just as on the surface of the
Earth, 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
(118°); similarly, you could locate the constellation Ursa Major
by its position on the celestial sphere:
The most common mistake of the beginning observer is to
“overpower” the telescope and use high magnifications which
the telescope’s aperture and typical atmospheric conditions
cannot reasonably support. Keep in mind that a smaller but
bright and well-resolved image is far superior to a larger but dim
and poorly resolved one. Powers above about 200x should be
employed only under the steadiest atmospheric conditions.
Most observers will want to have 3 or 4 eyepieces and perhaps
the Series 4000 #140 2x Barlow Lens to achieve the full range
of reasonable magnifications. See OPTIONAL ACCES¬
SORIES, page 11, for further details.
R.A.: 11 hr; Dec:+50°.
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 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°) (Fig. 9). 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° O’ 0".

- 9 -
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 Ohr Omin Osec 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 (Ohr Omin
Osec) carry increasing R.A. coordinates.
All celestial objects are specified in position by their celestial
coordinates of Right Ascension and Declination. The
telescope's Dec and R.A. setting circles (1) and (3), Fig. 10,
may be dialed to the coordinates of a specific celestial object,
which may then be located without a visual search. However,
before making use of the telescope’s setting circles to locate
celestial objects, your telescope must first be polar aligned.
Fig. 10: R.A. and Dec Controls. (1) Dec Setting Circle; (2) R.A.
Slow-Motion Control; (3) R.A. Setting Circle; (4) Dec Slow-Motion
Control.
Polar Alignment
Celestial objects are essentially fixed on the Celestial Sphere.
However, they appear to move across the sky in an arc as the
Earth rotates on its axis, with a complete rotation of the Earth
occurring once in every 24 hour period. This apparent motion is
not obvious to the unaided eye, but, when viewed through a
telescope, this motion is rapid indeed. Objects centered in the
telescope move entirely out of the field of view in 15 to 60
seconds, depending upon the magnification employed.
During the 24 hour period of the Earth's rotation, stars make one
complete revolution about the Celestial Pole, making concentric
circles with the Celestial Pole at the center. By lining up the
telescope’s polar axis (19), Fig. 1, with the North Celestial
Pole (or South Celestial Pole if observing from the Earth's
southern hemisphere), celestial objects may be followed
(tracked) by moving the telescope about only one axis, the
polar axis.
In addition, by polar aligning the telescope, the telescope's Dec
and R.A. setting circles (1) and (3), Fig. 10, may be used to
locate faint celestial objects directly from their catalogued
coordinates.
Polar Alignment Procedures:
Polar alignment consists of the following two operations
1. Pick up the entire telescope-and-tripod and orient the
tripod so t hat the leg directly beneath the counterweights
(the leg marked "N") points due north .
For observers in the southern hemisphere, pick up the
entire telescope-and-tripod and orient the tripod sojhat the
le g directly beneath the counterweights (the leg marked
"N"t points due south .
2. Determine the latitude of your observing location by
checking a road map or atlas. Then, adjust the latitude of
the telescope-and-tripod to indicate the latitude of your
observing location by turning the fine latitude adjustment
knob (3), Fig. 11, clockwise or counterclockwise until the
latitude pointer (1), Fig. 11, indicates the correct latitude on
the latitude scale (6), Fig. 11.
Fig. 11: Latitude Controls. (1) Latitude Pointer; (2) Latitude Lock
Lever (opposite side); (3) Fine Latitude Adjustment Knob; (4) Lock
Nut; (5) Latitude Lock Knob; (6) Latitude Scale,
It may be necessary to loosen the lock nut (4). Fig. 11, to
allow enough movement of the mount to achieve the
desired latitude. When the desired latitude has been
achieved, tighten the lock nut until the nut is flush against
the mount.
Step (1), above, is equivalent to pointing the telescope's polar
axis (19), Fig. 1, due north (or due south for observers in the
southern hemisphere). Step (2) is equivalent to making the
telescope's latitude angle (26), Fig. 1. equal to the latitude angle
of your observing location.
With (1) and (2) accomplished, the telescope is sufficiently well
polar aligned for most visual observing applications.
For the majority of telescope applications, this procedure is
entirely satisfactory. For those interested in astrophotography,
or those interested in utilizing the telescope's setting circles to
locate faint objects, a more precise polar alignment is
necessary, requiring the optional #812 Polar Alignment Finder
(see OPTIONAL ACCESSORIES, page 11).
Note: The Fine Azimuth Adjustment Knobs (14), Fig. 1, are
generally only utilized during the precise polar alignment
procedure described in the instructions accompanying the #812
Polar Alignment Finder.
Locating North by using Polaris, the North Star, is adequate for
the purposes discussed above. Polaris can be found in relation
to the Big Dipper by projecting a line from the so-called "pointer
stars” of the Big Dipper (see Fig. 12). For southern hemisphere
alignment, locate south by using the faint star Sigma Octans
(the South Star).

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2. Avoid setting up the telescope inside a room and observing
through an open window (or, worse, a closed window!) In
such a case, air currents caused by differences in
indoor/outdoor temperatures make quality astronomical
optical performance impossible.
Note: A practical exception to the above rule is the case where
the telescope is, for example, set up in a living room or den for
observing an outdoor terrestrial scene or view through a closed
window. At low powers (up to about 60x) the telescope will
perform reasonably well in this application, but the observer
should understand dearly that optical performance under these
conditions cannot approach the performance that will be
realized if the telescope were instead set up outside.
3. As discussed above, avoid “overpowering” the telescope.
If the terrestrial or astronomical image becomes fuzzy at
high powers, drop down to a lower power. Image
degradation at high powers is not due to any fault of the
telescope but is caused by heat waves and turbulence in
the earth's atmosphere. Astronomical observations at high
powers (i.e., above about 200x) should be undertaken only
when the atmosphere is very steady, as confirmed by an
absence of "twinkling” in star images.
4. Try not to touch the eyepiece when observing through the
telescope. Vibrations in your hand are immediately
transferred to the telescopic image.
5. If an observer wears eyeglasses and does not suffer from
astigmatism, he or she should take off the glasses when
using the telescope; the telescope's magnification
compensates for near- or farsightedness. Observers with
astigmatism should, however, wear their glasses, since the
telescope cannot compensate for this eye defect.
6. Allow your eyes to become “dark adapted" before
attempting serious astronomical observations through the
telescope. Night adaptation normally requires about 10 to
15 minutes.
7. As you use your telescope more and more for astronomical
observing, you will find that you are seeing finer and finer
detail — on the surface of Jupiter, for example. Observing
through a fine optical instrument is, to some degree, an
acquired skill. Celestial observing becomes increasingly
rewarding as your eye becomes better trained in the
detection of subtle variations of color, contrast, and
resolution.
TERRESTRIAL OBSERVING
Although principally designed for astronomical observing, the
Model 102ACHR/500 telescope makes an excellent terrestrial
observing tool. The telescope’s controls are utilized in the same
manner as for astronomical applications, but there are
differences when locating and observing terrestrial subjects due
to image orientation through the telescope.
Image Orientation
The viewfinder presents an inverted image which appears
upside-down and reversed lett-for-right. With the standard-
equipment diagonal prism and PL 25mm eyepiece in place in
the main telescope, terrestrial images appear right-side-up. but
reversed left-for-right. This orientation is usually acceptable tor
terrestrial observing, except in the case of reading a distant sign
or automobile license plate, for example.
Terrestrial image orientation can be fully corrected with the
optional Meade #928 45° Erect-Image Diagonal Prism (see
OPTIONAL ACCESSORIES, below).
OPTIONAL ACCESSORIES
A wide assortment of professional Meade accessories is
available for the Model 102ACHR/500 telescope. The premium
quality of these accessories is well-suited to the quality of the
instrument itself.
Eyepieces
Meade Series 4000 Super Plossl (SP), Super Wide Angle
(SWA), and Ultra Wide Angle (UWA) Eyepieces, in the standard
American-size (1.25") barrel diameter, permit a range of
magnifying powers with the telescope. Powers obtained with
each eyepiece are as follows:
Eyepiece Power
SP 6.4mm 144x
SP 9.7mm 95x
SP 12.4mm 74x
SP 15mm 61 x
SP 20mm 46x
SP 26mm 35x
SP 32mm 29x
SP 40mm 23x
SWA 13.8mm 67x
SWA 18mm 51 x
SWA 24.5mm 38x
UWA 4.7mm 196x
UWA 6.7mm 137x
Meade Super Plossl and Super Wide Angle Eyepieces are ideal
for general-purpose astronomical or terrestrial observing. The
typical Model 102ACHR/500 user may wish to add 2 or 3 of
these eyepieces to his or her telescope. An introductory
selection might include the SP 9.7mm and SP 15mm.
The more advanced observer will perhaps select the SP 9.7mm,
SP 12.4mm. and SWA 18mm. The Super Wide Angle Eyepiece
series yields extremely wide fields of view, perfect for the
examination of star fields, diffuse nebulae, or for terrestrial
applications.
Under very steady seeing conditions Meade UWA 4.7mm and
6.7mm eyepieces present the widest fields of view obtainable at
high powers and are excellent eyepieces for the Moon and
planets.
#140 2x Barlow Lens
An amplifying lens, the Series 4000
#140 2x Barlow doubles the power
o any eyepiece with which it is
used. Insert the #140 into the
telescope's eyepiece-holder first, followed by the diagonal prism
and eyepiece.
Example: For the Model 102ACHR/500, the standard
equipment PL 25mm eyepiece yields a power of 37x: when used
in conjunction with the Series 4000 #140 2x Barlow Lens, this
eyepiece yields 74x.