Meade Polaris 127mm User Manual - Page 23

grasping the secondary holder with your hand, tilt the secondary mirror holder 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 secondary mirror collimation screws to lock the holder in place. Then, if necessary, make adjustments to these 3 Phillips-head screws to refine the tiltangle of the secondary mirror until the entire primary mirror can be seen centered within the secondary mirror reflection. When the secondary mirror is correctly aligned, it will look like Fig. 16 (Note: The primary mirror is shown out of alignment). C. PRIMARY MIRROR ADJUSTMENTS If the secondary mirror (1, Fig. 16) and the reflection of the primary mirror (2, Fig. 16) appear centered within the draw tube (3, Fig. 16), but the reflection of your eye and the reflection of the secondary mirror (4, Fig. 16) appear off center, you will need to adjust the primary mirror tilt screws of the primary mirror cell (2, Fig. 13). These primary tilt screws are located behind the primary mirror, at the lower end of the main tube. To adjust the primary mirror tilt screws (2, Fig 13), first turn by several turns, the primary mirror cell lock knobs (3, Fig. 13) that are next to each primary mirror tilt screw. The three primary mirror cell locking screws are Phillips head screws on all Polaris models. Then by trial-and-error, turn the primary mirror tilt knobs (2, Fig. 13) until you develop a feel for which way to turn each knob to center the reflection of your eye. Once centered, as in Fig. 14, turn the 3 primary mirror cell locking screws (3, Fig. 13) to re-lock the tilt-angle adjustment. NOTE: Some models have large thumb knobs for the primary mirror cell tilt knobs(2, Fig 13). Other models have Phillips head screws as the primary mirror cell tilt screws. On these models, the primary mirror cell tilt screws (2, Fig 13) are the screws that have the screw heads touching the rear cell. D. STAR TESTING THE COLLIMATION With the collimation performed, you will want to test the accuracy of the alignment on a star. Use the 25mm eyepiece and point the telescope at a moderately bright (second or Looking at or near the Sun will cause irreversable damage to your eye. Do not point this telescope at or near the Sun. Do not look through the telescope as it is moving. third magnitude) star, then center the star image in view. With the the star telescope's field-ofcentered follow the 21 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. 17C. (An improperly aligned telescope will reveal elongated circles (Fig. 17A), with an off-center dark shadow.) •If the out-of-focus star disk appears elongated (Fig. 17A), you will need to adjust the primary mirror adjusting tilt screws of the primary mirror cell (3, Fig. 13) •To adjust the primary mirror tilt screws (3, Fig. 13), first unscrew several turns the 3 hex-head primary mirror cell locking screws (2, Fig. 13), to allow free turning movement of the tilt knobs. •Using the flexible cable controls move the telescope until the star image is at the edge of the field-of-view in the eyepiece, as in Fig.