Orion 9535, 9533, 9536 Collimating the StarSeeker 114mm, Collimating the StarSeeker 130mm

Figure 11. The view of a collimated telescope as seen through the focuser of the StarSeeker 114mm and 130mm reflectors.

and 130mm, however, have collimation screws that can be used to adjust the alignment of the primary mirror.

To check if your telescope is in collimation refer to figure 6-1. If you look into the eyepiece adapter (without an eyepiece) at the top of the focuser, this is what you should see. If the reflec- tion of your eye is off center, then collimating is necessary.

The StarSeeker 114mm and 130mm reflectors come with a collimating cap. This is a simple cap that fits on the focuser drawtube like a dust cap, but has a hole in the center and a silver bottom. This helps center your eye so that collimating is easy to perform.

In addition to the collimating cap, you’ll notice a small ring label on the exact center of the primary mirror. This “center mark” allows you to achieve a very precise alignment of the primary mirror; you don’t have to guess where the center of the mirror is. You simply adjust the primary mirror position (described below) until the reflection of the hole in the col- limating cap (the “dot”) is centered inside the ring.

NOTE: The center ring sticker need not ever be removed from the primary mirror. Because it lies directly in the shadow of the secondary mirror, its presence in no way adversely affects the optical performance of the tele- scope or the image quality. That might seem counter- intuitive, but it’s true!

Collimating the StarSeeker 114mm

Adjustments to the collimation of the telescope can be made by turning the collimation adjustment knobs located at the rear of the optical tube (Figure 12). First loosen the three Phillips head screws on the rear cell of the tube. Turn each collimation knob, one at a time, until the reflected image of the collimating cap’s dot in the secondary mirror is centered in the primary mirror center mark ring. Once the telescope is col- limated, tighten the Phillips head screws until you feel a slight resistance. Do not over tighten the screws.

Support screws

Collimation screws

Figure 12. Collimation adjustment screws for the StarSeeker 114mm and 130mm.

Rear cover plate

Figure 13. To access the collimation adjustment screws, the rear cover plate must first be removed.

Collimating the StarSeeker 130mm

To perform collimation adjustments, the rear cover plate must first be removed. This is done by unthreading the three small Phillips-head screws on the back of the mirror cell (Figure 13). Once the cover plate is removed, the collimation adjustment screws are accessible (Figure 12).

Collimation adjustments are made by adjusting the three pairs of collimation screws. The collimation screws can be turned with a Phillips head screwdriver and a 2.5mm hex key. Each pair of collimation screws work together to adjust the align- ment of the primary mirror; one screw must be loosened and the other tightened by the same amount. Try tightening and loosening one of the pairs of collimation screws by one turn. Look into the focuser to see if the secondary mirror reflection has moved closer to the center of the primary mirror reflec- tion. The collimating cap makes this easy to see; watch if the “dot” of the collimating cap is moving closer or farther away from the ring on the center of the primary mirror. Repeat this process on the other two pairs of collimation screws, if nec- essary. It will take a little trial and error to get a feel for how to adjust the screw pairs to center the dot of the collimating cap in the ring of the primary mirror mark. Once the dot is centered in the ring, the telescope is collimated, and the rear cover plate can be reinstalled on the back of the mirror cell.

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