Secondary mirror collimation adjustment screws
Do not adjust center screw.
Figure 7: The secondary mirror collimation adjustment screws.
2.Slide the chrome portion of the eyepiece into the star diagonal.
3.Tighten the setscrew on the star diagonal to hold the eyepiece in place.
To remove the eyepiece, loosen the setscrew on the star diagonal and slide the eyepiece out. You can replace it with another eyepiece (purchased separately).
Image Orientation
The image orientation changes depending on how the eye- piece is inserted into the telescope. When using the star diag- onal, the image is right side up but reversed from left to right (i.e., mirror image). If inserting the eyepiece directly into the focuser without the star diagonal, the image is will be upside- down and reversed from left to right (i.e., inverted). This is normal for the Ritchey-Chrétien design.
Collimating the
Ritchey‑Chrétien
The optics in your new Ritchey-Chrétien optical tube have been aligned at the factory. However, rough handling during transit may require periodic re-adjustments. We have center- marked the secondary mirror and included a collimation eye- piece to aid in this process.
Using the Collimating Eyepiece
This is the recommend procedure for most users. Set up your telescope in a well-lit room with the telescope pointed horizontally. It is best to remove the lens cover and point the telescope at a white (or light colored) wall. Remove all of the extension rings and attach the focuser directly to the optical tube. Insert the collimation eyepiece into the focuser using the 1.25" eyepiece adapter. When peering through the collimation eyepiece you should see a small black dot centered within a
Collimation
adjustment
Opticalpush-pull screws axis
Figure 8: The Ritchey-Chrétien with the focuser removed to show the three sets of optical axis adjustment screws. For illustration only: do not remove the focuser when performing collimation.
donut-like ring (Figure 9). The central black dot is the mark of the collimation eyepiece and the ring is the center target on the secondary mirror. The big white circle outside that is the reflected surface of the collimation eyepiece and the larger black circle outside that is the secondary holder. The optical axis is denoted by a thin white circle on the outer edge. You can disregard that for the time being; it will be covered in the following section. If this is aligned as in Figure 9a, no further adjustments will be necessary. If it appears as in Figure 9b
—with the dot of the collimation eyepiece not centered in the secondary center mark — adjust the three collimation screws at the front of the secondary mirror holder. This will adjust the tilt of the secondary changing the relative position of the sec- ondary mark when peering through the collimation eyepiece.
Secondary Adjustment
NOTE: Only adjust the three screws around the perimeter of the holder. Do not adjust the center screw. Adjusting the center screw can cause the secondary mirror to fall off and will not be covered under warranty (Figure 7).
A 4mm hex key is required to perform collimation on the sec- ondary mirror. When adjusting one of these screws you will need to make equal counter-adjustments to the other two. Therefore, if you are tightening one screw you will need to loosen, by an equal amount, the other two. When the process is complete you should have tension against all three screws. Adjust the screws by no more than ¼ turn at a time. Only minor adjustments should be required to achieve collimation. This will also aid in the prevention of accidently putting the telescope grossly out of collimation. Experiment with different combinations until the collimation eyepiece mark is centered in the center ring of the secondary mirror. The correct align- ment of the secondary mirror is critical in determining if the optical axis requires alignment. Be certain you have properly aligned the secondary mirror before proceeding to the next step.
