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A. Introducing the Meade Model 4500
The Model 4500 is an easy-to-operate, high performance 4.5" (114mm)
reflecting telescope, intended for astronomical observing. Equipped with
a deluxe equatorial mount and aluminum tripod, the telescope's motion is
continuously adjustable for tracking celestial objects. Your telescope comes
to you ready for adventure; it will be your companion in a universe of planets,
galaxies, and stars. Please note that the Model 4500 is a Newtonian reflecting
telescope optimized for astronomical observing performance and is not intended
for terrestrial observing.
Figure 1: Meade Model 4500: 4.5" Equatorial Reflecting Telescope
1. Tripod legs
2. Equatorial mount
3. R.A. flexible cable control
4. Dec. flexible cable control
5. Counterweight
6. Counterweight shaft
7. Counterweight lock
8. Safety washer/thumbscrew
9. Latitude lock
10. Polar axis
11. Latitude adjustment knob
12. Optical tube assembly
13. Optical tube saddle plate
14. Cradle rings
15. Cradle ring lock knobs
16. Viewfinder bracket mounting bolts
17. Focuser
18. Focuser thumbscrew
19. Eyepiece
20. Viewfinder bracket
21. Declination axis
22. R.A. lock
23. Dec. lock
24. 6 x 30 viewfinder
25. Telescope front dust cover
26. Viewfinder bracket thumbscrews
27. R.A. setting circle
28. Dec. setting circle
29. Latitude dial
30. Azimuth lock
31. Focus knobs
32. Polar shaft acorn cap nut
33. Azimuth base
34. Azimuth shaft bolt
35. R.A. worm block assembly
36. Dec. worm block assembly
37. Cradle ring attachment knobs
38. Tripod leg Phillips-head fastener screws
39. Tripod-to-mount attachment points
40. Accessory shelf
41. Accessory shelf central mounting knob
42. Tripod leg brace supports
43. Tripod leg lock knobs
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1. This Manual
These instructions detail the set-up, operation, specifications, and optional
accessories of your Meade Model 4500. In order that you may achieve maximum
enjoyment of the instrument, we urge that you take a few minutes to read
all of this manual before making first observations through the telescope.
As you read this manual, the technical terms associated with telescopes
will be made clear.
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2. Standard Equipment
- Complete optical tube assembly with a 4.5" (114mm) diameter primary
mirror, viewfinder mounting bolts with mounting nuts and 1.25" rack-and-pinion
focuser. Mirror focal length = 910mm; f/8.
- Equatorial mount with pre-attached heavy duty, continuously adjustable,
aluminum tripod and leg braces.
- Accessories:
- MA25mm (36X) eyepiece (1.25"O.D.)
- Cradle rings with lock knobs
- 6 x 30 viewfinder and bracket
- Counterweight with counterweight shaft
- Flexible cable controls for both telescope axes
- Accessory shelf with mounting knob
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B. Unpacking and Assembly
Your Meade Model 4500 comes to you packaged almost entirely pre-assembled.
You will find upon opening the giftbox that there are two compartments within
that contain the optical tube assembly and the tripod with equatorial mount.
The accessories described above will be located within compartments custom-cut
into the styrofoam block inserts. (References herein [e.g., (6)] are
to Fig.1 unless otherwise specified.)
- Remove and identify the telescope's Standard Equipment listed in Section
A.2., above.
- The three tripod lock knobs (43) have been removed from the bottom section
of each tripod leg to insure safe arrival of the tripod assembly. To install,
thread in each tripod lock knob into the threaded hole located at the right
side of each of the three gray colored castings (see Fig.1 inset)
at the bottom of each tripod leg. Tighten the tripod lock knob only to a
"firm feel" to avoid damage to the tripod caused by overtightening.
- Spread the tripod legs (1) to full extension so that the leg braces
(42) are taut (should one of the tripod leg braces slip out of the center
triangle fastener, merely reposition the brace and slide it back into position).
Adjust the tripod with the attached equatorial mount (2) to the desired
height by loosening the tripod lock knobs and extend the sliding inner section
of each tripod leg; then tighten each knob.
- Remove the mounting knob (41) from the round accessory shelf (40). Place
the accessory shelf on top of the center triangle leg brace fastener of
the tripod (1) so that the threaded stud protruding from the bottom of the
shelf (40) passes through the hole in the center. Then replace and tighten
the accessory shelf mounting knob (41).
- Attach the flexible cable controls (3) and (4). These cable controls are
secured in place with a firm tightening of the thumbscrew located at the
end of each cable.
- Holding the counterweight (5) firmly in one hand, slip the counterweight
onto the counterweight shaft (6). Attach the counterweight (5) and counterweight
shaft (6), by supporting the unlocked (7) counterweight firmly in one hand,
while threading the counterweight shaft into the base of the Declination
axis of the telescope's equatorial mount with the other (see Fig. 1). Once
firmly attached, slide the counterweight to the midpoint on the counterweight
shaft and secure it in place with the lock knob (7) of the counterweight.
Note: If the counterweight ever slips, the secured threaded safety washer/knob
(8) will not let the weight slide entirely off the counterweight shaft.
Be certain that this safety washer/knob is always in place.
- Release the latitude lock (9) of the equatorial mount, and tilt the polar
axis (10) of the telescope to roughly a 45° angle by turning the latitude
adjustment knob (11). With the polar axis thus tilted, firmly re-tighten
the latitude lock.
- Loosen the lock knobs (15) of the cradle rings (14) and open the cradle
rings to position them over the optical tube assembly (12). Turn the lock
knobs a few turns to keep the cradle rings closed, but to still allow the
cradle rings to slide freely up-and-down the main tube.
- Remove the viewfinder bracket mounting nuts from the viewfinder bracket
mounting bolts (16) that protrude from the optical tube (12), near the focuser.
Place the viewfinder bracket's mounting holes (located at the base of the
bracket) over the mounting bolts, so that the bracket is oriented as shown
in Fig. 1. Replace the viewfinder bracket mounting nuts, and tighten to
a firm feel. Then center the viewfinder in both bracket rings by backing
off the three thumbscrews (26) on each bracket ring. Orient the viewfinder
so its front objective lens is pointing in the same direction as the open
end (front) of the optical tube (25).
- While firmly holding the optical tube (12), position it onto the optical
tube saddle plate (13), with the mid-point of the optical tube's length
lying roughly in the center of the saddle plate. Then slide the cradle rings
(14) over the saddle plate of the mount. Tighten the cradle ring attachment
knobs (37) to a firm feel when the cradle rings are positioned over the
telescope's saddle (13). Then tighten the cradle ring lock knobs (15) to
a firm feel; do not overtighten these knobs. Please note that you may want
to change the rotational position of the optical tube to gain a more comfortable
observing position of the focuser (17). This adjustment may be performed
several times in one observing session, as desired.
- Insert the MA25mm eyepiece (19) into the focuser, and tighten the focuser
thumbscrew (18) to secure the eyepiece.
The telescope is now fully assembled. Before it can be properly used, however,
the telescope must be balanced and the viewfinder aligned.
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1. Balancing the Telescope
In order for the telescope to move smoothly on its mechanical axes, it must
first be balanced about the 2 telescope axes: the polar axis (10) and the
Declination axis (21). All motions of the polar aligned telescope (more
on this later) take place by moving about these two axes, separately or
simultaneously. To obtain a fine balance of the telescope, follow the method
below:
- Loosen the R.A. lock (22) and rotate the telescope so that the counterweight
shaft (6) is parallel to the ground (horizontal).
- Slide the counterweight along the counterweight shaft until the telescope
remains in one position without tending to drift down in either direction.
Then tighten the counterweight lock knob (7), locking the counterweight
in position.
- Lock the R.A. lock (22), and unlock the Declination lock (23). The telescope
will now turn freely about the Declination axis. Loosen the cradle ring
lock knobs (15) so that the main tube in the cradle rings slides easily
up-or-down in the cradle rings. Move the main tube in the cradle rings until
it is balanced rotationally about the Declination axis. Re-lock the knobs
(15).
The telescope is now properly balanced on both axes.
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2. Alignment of the Viewfinder
The wide field of view provided by the 6 x 30mm viewfinder permits easy
object sighting prior to observation in the higher-power main telescope.
The 6 x 30 Viewfinder (24) and viewfinder bracket (20) should be attached
to the telescope tube assembly as described above (see Figure 1). In order
for the viewfinder to be functional, however, it must be aligned to the
main telescope, so that both the viewfinder and main telescope point at
the same position in the sky. With this simple alignment performed, finding
objects is greatly facilitated, since you will first locate an object in
the wide-field viewfinder, then you will look in the eyepiece of the main
telescope for a detailed view. To align the viewfinder follow these steps:
- Remove the telescope front dust cover (25), and the dust covers of the
viewfinder.
- Place the low- power (MA25mm) eyepiece into the focuser of the main telescope.
- Unlock the R.A. lock (22) and the Dec. lock (23) so that the telescope
turns freely on both axes. Then point the main telescope at some well-defined
land object (e.g., the top of a telephone pole) at least 200 yards
distant, and re-lock the R.A and Dec. axes. Turn the flexible cable controls,
(3) and (4), to center the object in the telescopic field.
- With the front of the viewfinder already centered in the front bracket
ring, look through the viewfinder and loosen or tighten, as appropriate,
one or more of the rear viewfinder bracket ring thumbscrews (26) until the
viewfinder's crosshairs are likewise centered on the object previously centered
in the main telescope.
- Check this alignment on a celestial object, such as a bright star or the
Moon, and make any refinements necessary, using the method outlined above.
With this alignment performed, objects first located in the wide-field viewfinder
will also be centered in the main telescope's field of view. (Note: The
viewfinder and telescope present an image which is upside-down.)
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C. Understanding Celestial Movements and Coordinates
To line up the Model 4500 with the pole, follow this procedure:
- Release the Azimuth lock (30) of the Azimuth base (33), so that the entire
telescope-with-mounting may be rotated in a horizontal direction. Rotate
the telescope until the polar axis (10) points due North. Use a compass
or locate Polaris, the North Star (see diagram),
as an accurate reference for due North.
- Level the mount, if necessary, by adjusting the heights of the three
tripod legs.
- Determine the latitude of your observing location by checking a road
map or atlas. Release the latitude lock (9) and tilt the telescope mount
with the latitude adjustment knob (11) so that the pointer indicates the
correct latitude of your viewing location on the latitude scale (29). Re-tighten
the latitude lock (9).
- If steps (1) - (3) above were performed with reasonable accuracy, your
telescope is now sufficiently well-aligned to the North Celestial Pole for
visual observations.
Once the mount has been polar-aligned as described above, the latitude angle
need not be adjusted again unless you move to a different geographical
location (i.e. a different latitude). The only polar alignment procedure
that need be done each time you use the telescope is to point the polar
axis due North, as described in step (1) above.
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D. Using the Telescope
With the telescope assembled, balanced and polar aligned as described above,
you are ready to begin observations. Decide on an easy-to-find object such
as the Moon, if it is visible, or a bright star, to become accustomed to
the functions and operations of the telescope. For the best results during
observations, follow the suggestions below:
- To center an object in the main telescope, loosen the telescope's R.A.
lock (22) and Dec. lock (23). The telescope can now turn freely on its axes.
Use the aligned viewfinder to first sight-in on the object you wish to observe;
with the object centered on the viewfinder's crosshairs, re-tighten the
R.A. and Dec. locks.
- If you have purchased an assortment of eyepieces always start an observation
with a low power eyepiece (e.g., the MA25mm eyepiece); get the object
well-centered in the field of view and sharply focused. Then try the next
step up in magnification. If the image starts to become fuzzy as you work
into higher magnifications, then back down to a lower power; the atmospheric
steadiness is not sufficient to support high powers at the time you are
observing. Keep in mind that a bright, clearly resolved but smaller image
will show far more detail than a dimmer, poorly resolved larger image. The
MA25mm eyepiece included with the Model 4500 presents a wide field of view,
ideal for general astronomical observing of star fields, clusters of stars,
nebulae, and galaxies; it is also probably the best eyepiece to use in the
initial finding and centering of any object.
- Once centered, the object can be focused by turning one of the knobs of
the focusing mechanism (31). You will notice that the astronomical object
in the field of view will begin to slowly move across the eyepiece field.
This motion is caused by the rotation of the Earth on its axis, as described
in Section C, although the planets and stars, are, for practical purposes,
fixed in their positions in the sky. The platform on which the telescope
is sitting (the Earth) rotates once every 24 hours under these objects.
To keep astronomical objects centered in the field of the polar aligned
telescope, simply turn the R.A. flexible cable control (3). These objects
will appear to move through the field more rapidly at higher powers. Note
that the Declination flexible cable control is used only for centering purposes,
and not for tracking.
- Avoid touching the eyepiece while observing through the telescope. Vibrations
resulting from such contact will cause the image to move. Likewise, avoid
observing sites where ground-based vibrations may resonate the tripod. Viewing
from the upper floors of a building may also introduce image movement.
- You should allow a few minutes to allow your eyes to become "dark
adapted" before attempting any serious astronomical observations. Use
a red filtered flashlight to protect your night vision when reading star
maps or inspecting the components of the telescope.
- Avoid setting up the telescope inside a room and observing through an
open window (or worse yet, a closed window). Images viewed in such a manner
may appear blurred or distorted due to temperature differences between inside
and outside air. Also, it is a good idea to allow your telescope a chance
to reach the ambient (surrounding) outside temperature before starting an
observing session.
- Avoid viewing objects low on the horizon. Objects will appear better
resolved with far greater contrast when viewed higher in the sky. Also,
if images appear to "shimmer" in the eyepiece, reduce power
until the image steadies. This condition is caused by air turbulence in
the upper atmosphere.
The Meade Model 4500 may be used for a lifetime of rewarding astronomical
observing, but basic to your enjoyment of the telescope is a good understanding
of the instrument. Read the above instructions carefully until you understand
all of the telescope's parts and functions. One or two observing sessions
will serve to clarify these points forever in your mind.
The number of fascinating objects visible through your Meade reflector is
limited only by your own motivation. Astronomical software, such as Meade's
AstroSearch, or a good star atlas, such as Meade Star Charts will assist
you in locating many interesting celestial objects. These objects include:
- Cloud belts across the surface of the planet Jupiter.
- The 4 major satellites of Jupiter, visible in rotation about the planet,
with the satellite positions changing each night.
- Saturn and its famous ring system, as well as several satellites of
Saturn, much fainter than the major satellites of Jupiter.
- The Moon: A veritable treasury of craters, mountain ranges and fault
lines. The best contrast for viewing the Moon is during its crescent phase.
The contrast during the full Moon phase is low due to the angle of illumination.
- Deep-Space: Nebulae, galaxies, multiple star systems, star clustershundreds
of such objects are visible through the Model 4500.
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E. Using Setting Circles
Setting circles of the polar aligned equatorial mount can facilitate the
location of faint celestial objects not easily found by direct visual observation.
To use the setting circles, follow this procedure:
- Use a star chart or star atlas, and look up the celestial coordinates,
Right Ascension and Declination (R.A. and Dec.), of an easy-to-find bright
star that is within the general vicinity of the faint object you wish to
locate.
- Center the determined bright star in the telescope's field of view.
- Manually turn the R.A. setting circle (27) to read the R.A. of the object
now in the telescope's eyepiece.
- The setting circles are now calibrated (the Dec. setting circle (28) is
factory calibrated). To locate a nearby faint object using the setting circles
determine the faint object's celestial coordinates from a star chart, and
move the telescope in R.A. and Declination until the setting circles read
the R.A. and Dec. of the object you are attempting to locate. If the above
procedure has been carefully performed, the faint object will now be in
the field of a low power eyepiece.
The R.A. Setting Circle must be manually re-calibrated on the current Right
Ascension of a star every time the telescope is set up, and reset to the
centered object's R.A. coordinate before moving to a new R.A. coordinate
setting. The R.A. Setting Circle has two sets of numbers, the inner set
is for Southern hemisphere use while the outer set of numbers (the set closest
to the R.A. gear), is for use by observers located North of the Earth's
equator (e.g., in North America).
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F. Calculating Power
The power, or magnification of the telescope depends on two optical characteristics:
the focal length of the main telescope and the focal length of the eyepiece
used during a particular observation. For example, the focal length of the
Model 4500 telescope is fixed at 910mm. To calculate the power in use with
a particular eyepiece, divide the focal length of the eyepiece into the
focal length of the main telescope. For example, using the MA25mm eyepiece
supplied with the Model 4500, the power is calculated as follows:
Power = 910mm ÷ 25mm= 36X
Meade Instruments manufactures several types of eyepiece designs that
are available for your telescope. The type of eyepiece ("MA"
Modified Achromatic, "SP" Super Plössl, etc.) has no bearing
on magnifying power but does affect such optical characteristics as field
of view, flatness of field, eye-relief, and color correction.
The maximum practical magnification is determined by the nature of the object
being observed and, most importantly, by the prevailing atmospheric conditions.
Under very steady atmospheric "seeing," the Model 4500 may be
used at powers up to about 228X on astronomical objects. Generally, however,
lower powers of perhaps 75X to 175X will be the maximum permissible, consistent
with high image resolution. When unsteady air conditions prevail (as witnessed
by rapid "twinkling" of the stars), extremely high-power eyepieces
result in "empty magnification," where the object detail observed
is actually diminished by the excessive power.
Assorted eyepieces are available both to increase and decrease the operating
eyepiece power of the telescope. If the Model 4500 is used on a regular
basis, a selection of four to five eyepieces is recommended. For example,
an eyepiece assortment of focal lengths 40mm, 25mm, 12.5mm, 9mm, and 6mm
yields a magnifying range of 22.5X, 36X, 72X, 101X, and 150X respectively.
A high quality Barlow Lens, such as the Meade #126 2x Telenegative Barlow
Lens, serves to double the power of each of these eyepieces. To use the
Barlow Lens, insert the #126 unit into the telescope's focuser first, followed
by an eyepiece; the power thus obtained is then double the power obtained
when the eyepiece is used alone. For example, the MA25mm eyepiece, when
used in conjunction with the #126 2x Telenegative Barlow Lens yields 72X.
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G. Maintenance
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1. Cleaning
As with any quality instrument, lens or mirror surfaces should be cleaned
as infrequently as possible. Front surface aluminized mirrors, in particular,
should be cleaned only when absolutely necessary. In all cases avoid touching
any mirror surface. A little dust on the surface of a mirror or lens causes
negligible loss of performance and should not be considered reason to clean
the surface. When lens or mirror cleaning does become necessary, use a camel's
hair brush or compressed air gently to remove dust. If the telescope's
dust cover is replaced after each observing session, cleaning of the optics
will rarely be required.
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2. Mount and Tripod Adjustments
Every Meade Model 4500 equatorial mount and tripod is factory inspected
for proper fit and function prior to shipment. It is unlikely that you will
need to adjust, or tighten these parts after receipt of the telescope. However,
if the instrument received unusually rough handling in shipment, it is possible
that some of these assemblies can be loose. To make adjustments you will
need a 1/2" or 11/16" socket or adjustable end wrench, a 5/64"
hex wrench, and a Phillips-head screwdriver.
The equatorial mount has four main areas that can be adjusted: A loose polar
shaft can be tightened by releasing a 5/64" hex set-screw that is on
the side of the 11/16" polar shaft acorn cap nut (32), and then turning
the 11/16" acorn cap nut clockwise to a firm feel, and then tightening
the 5/64" hex set-screw. A loose Azimuth base (33), can be tightened
by turning the 11/16" Azimuth shaft bolt (34), located underneath the
mount and in between the three tripod legs, clockwise to a firm feel. The
R.A. (35), and Dec. (36) worm block assemblies can have backlash removed
by releasing the 2 Phillips-head screws on each assembly, applying pressure
to the worm block against the worm gear, and then tightening the Phillips-head
screws. Note that overtightening of any of the nuts, bolts, or screws can
inhibit the smooth rotating action of the axes and gears, and may result
in stripping the threads.
The tripod legs have 1/2" nuts (39), and Phillips-head screws (38)
that may have backed off, may also be tightened to a firm feel for the most
sturdy performance of the telescope.
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3. Collimation (Alignment) of the Optics
All Meade Model 4500 telescopes are optically aligned at the factory prior
to shipment. It is unlikely that you will need to align, or collimate, the
optics after receipt of the instrument. However, if the telescope received
unusually rough handling in shipment, it is possible that the optics must
be re-aligned for best optical performance. In any case this alignment procedure
is simple, and requires only a few minutes the very first time the telescope
is used. Take the time to familiarize yourself with the following collimation
procedure, so that you will recognize a properly collimated instrument and
can adjust the collimation yourself, if necessary.
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a. Correct collimation
The properly collimated (aligned) mirror system in the Model 4500 assures
the sharpest images possible. This occurs when the primary mirror and diagonal
mirror are tilted so that the focused image (see diagram)
falls directly through the center of the focuser drawtube (17, Fig.
1). These mirror tilt adjustments are made with the diagonal assembly
(Fig. 5) and the primary mirror cell (Fig.
6), and will be discussed later.
To inspect the view of the mirror collimation, look down the focuser drawtube
with the eyepiece removed. The edge of the focuser drawtube (1, Fig.
7), will frame the reflections of the primary mirror with the 3 mirror
clips (2, Fig. 7), the diagonal mirror (3,
Fig. 7) , the spider vanes (4, Fig.
7), and your eye (5, Fig. 7). Properly
aligned, all of these reflections will appear concentric (i.e. centered)
as illustrated in Figure 7. Any deviation from the concentric reflections
will require adjustments to the diagonal assembly (Fig.
5), and/or the primary mirror cell (Fig.
6).
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b. Spider vane adjustments
If the diagonal mirror (1, Fig. 8) is left
or right of center within the drawtube (2, Fig.
8), loosen the spider vane adjustment/lock knobs (1, Fig.
5) located on the outside surface of the main tube and slide the entire
diagonal assembly up or down the tube along the slotted holes, until the
diagonal mirror is centered in the drawtube.
If the diagonal mirror (1, Fig. 8) is above
or below of center within the drawtube, thread in one of the spider vane
adjustment/ lock knobs while unthreading the other. Only make adjustments
to 2 knobs at a time until the diagonal mirror is in the drawtube. When
the spider vane is correctly positioned, it will look like Fig.
9. (Note that the diagonal mirror is misaligned.)
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c. Diagonal holder adjustments
If the diagonal mirror (1, Fig. 9) is centered
in the drawtube (2, Fig. 9), but the primary
mirror is only partially visible in the reflection (3, Fig.
9), the 3 Phillips-head diagonal tilt screws (2, Fig.
5) must be unthreaded slightly to the point of where you can rotate
the diagonal holder (3, Fig. 5) from side-to-side
by grasping the diagonal holder with your hand and rotating until you see
the primary mirror become as centered in the reflection of the diagonal
mirror as possible. Once you are at the best position, thread in the 3 Phillips-head
diagonal tilt screws to lock the rotational position. Then, if necessary,
make adjustments to these 3 Phillips-head screws to refine the tilt-angle
of the diagonal mirror until the entire primary mirror can be seen centered
within the diagonal mirror reflection. When the diagonal mirror is correctly
aligned, it will look like Fig. 10. (Note
that the primary mirror is shown out of alignment.)
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d. Primary mirror adjustments
If the diagonal mirror (1, Fig. 10) and the
reflection of the primary mirror (2, Fig. 10)
appear centered within the drawtube (3, Fig. 10),
but the reflection of your eye and the reflection of the diagonal mirror
(4, Fig. 10) appear off-center, you will need
to adjust the primary mirror tilt Phillips-head screws of the primary mirror
cell (3, Fig. 6). These primary tilt screws
are located behind the primary mirror, at the lower end of the main tube.
See Fig. 4. To adjust the primary mirror tilt screws, first unscrew several
turns, the 3 hex-head primary mirror cell locking screws (2, Fig.
6) that are next to each primary mirror tilt Phillips-head screw. Then
by trial-and-error, turn the primary mirror tilt Phillips-head screws (3,
Fig. 6) until you develop a feel for which
way to turn each screw to center the reflection of your eye. Once centered,
as in Fig. 7, turn the 3 hex-head primary
mirror cell locking screws (2, Fig. 6) to
relock the tilt-angle adjustment.
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e. Star testing the collimation
With the collimation performed, you will want to test the accuracy of
the alignment on a star. Use the MA25mm eyepiece and point the telescope
at a moderately bright (second or third magnitude) star, then center the
star image in the telescope's field-of-view. With the star centered follow
the method below:
- Bring the star image slowly out of focus until one or more rings are visible
around the central disc. If the collimation was performed correctly, the
central star disk and rings will be concentric circles, with a dark spot
dead center within the out-of-focus star disk (this is the shadow of the
secondary mirror), as shown in Fig.11C. (An
improperly aligned telescope will reveal elongated circles (Fig.
11A), with an off-center dark shadow.)
- If the out-of-focus star disk appears elongated (Fig.
11A), you will need to adjust the primary mirror Phillips-head tilt
screws of the primary mirror cell (3, Fig. 6).
- To adjust the primary mirror tilt screws (3, Fig.
6), first unscrew several turns the 3 hex-head primary mirror cell locking
screws (2, Fig. 6), to allow free turning
movement of the tilt knobs.
- Using the flexible cable controls (3) and (4), Fig.
1, move the telescope until the star image is at the edge of the field-of-view
in the eyepiece, as in Fig. 11B.
- As you make adjustments to the primary mirror tilt screws (3, Fig.
6), you will notice that the out-of-focus star disk image will move
across the eyepiece field. Choose one of the 3 primary mirror tilt screws
that will move the star disk image to the center of the eyepiece field.
- Repeat this process as many times as necessary until the out-of-focus
star disk appears as in Fig. 11C, when the
star disk image is in the center of the eyepiece field.
- With the star testing of the collimation complete, tighten the 3 hex-head
primary mirror locking screws (2, Fig. 6).
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H. Specifications: Model 4500
Primary (main) mirror focal length: 910mm
Primary mirror diameter: 4.5" (114mm)
Focal ratio: f/8
Mounting: German equatorial
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