Meade 4500 instruction manual b. Spider vane adjustments, c. Diagonal holder adjustments, A, B, C

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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.)

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.)

Fig. 11A Fig. 11B Fig. 11C

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.

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