Advanced CT Laser Collimator Manual (V9.0 =OH=) Page 15 of 20
i.
The adjustments made with
Steps 11.1.c, .d, .g & .h
affect each other and are interactive. To achieve the best possible
collimation of the telescope (within the limits of the telescope’s construction) It is important to iterate
Steps 11.1.c, .g, & .h
until no further improvement can be achieved. The following Figures illustrate good alignment of a representative SCT.
Figure 11.1.i – Alignments seen After Completing
Step 11.1.i
1. Corrector Plate Centering –
Observing the Reflector Mirror
2. Corrector Plate Centering –
Observing the Reflector Mirror
3. Final Optics Tilt Adjustment –
Observing the Collimator Target Plate
5. A Look Inside After Step 11.1.i –
Secondary Mirror is Removed
4. Star De-Focused Telescope Photo –
Star Collimation Check Only
6. A Look Inside After Step 11.1.i –
Secondary Mirror is Removed
11.2. Mechanical Systems Used for Final Optics Axis Tilt Aiming Adjustment
This step presents the mechanical systems and their use to adjust the final optical (focuser, visual back, or tilt adjustable
reflector mirror) tilt axis. The necessary checks and observations that must be made using the Advanced CT Laser Collimator
to observe the status of the final optical tilt axis alignment – regardless of the mechanical system employed to control tilt – are
presented in
Step 11.1.d. & .h
. Use one of the following mechanical systems to adjust the final optical tilt axis:
a. Accessory Focuser Flange Tilt Setscrews (used in many Crayford focusers) – Some brands of Crayford accessory
focusers have tandem flanges that allow the “top” flange (closest to the eyepiece or camera) to rotate (or spin around)
separately from the flange closest to the telescope. This allows a convenient means of maintaining the relationship
between the camera or eyepiece and the focuser knobs or focus motor. Focusers with this feature often have tilt adjust
setscrews built into the top (rotating) flange. See the figure included in
Step 9.3
above. Note that the tilt adjustment
setscrews in this type focuser are set parallel to the optical axis. When the setscrews are adjusted they do a good job of
adjusting tilt within a somewhat limited range, but after tilt is adjusted the rotating feature of the “top” flange is lost, and it
can no longer be rotated and still maintain tilt alignment.
(Continued Next Page)
If the telescope
were constructed
perfectly the two Double Pass
Crosshairs would Overlap Perfectly.
Single Focal
Point Dot is centered.
Corollary to good
Star Collimation the De-
Focused Dots are Concentric.
Three Dots are
on the Same Ring.
If the telescope
were constructed perfectly the
Single Path Crosshair would be
perfectly Centered.
Camera Installed on Focuser –
No other changes made.