Actual Step

Step 3a: Secondary Mirror Collimation using a TS RCKOLLI Collimator

updated: 2024-05-08


Aligning the secondary mirror with the optical axis of the telescope

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Step 2: Check and correct Mirror Spacing

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Step 4: Adjusting the Primary Mirror


Insert the collimator into the 2" mount of your focuser. It is helpful to align the labeling with the collimation screws to make it easier. Gently press your hand against the back of the collimator. This will ensure that the collimator is optimally positioned in the focuser. Tighten the collimation screws slightly. Switch on the collimator in Newtonian/Reflector mode (red LEDs). 

WARNING: It is better not to touch the central locking screw on the second mirror, as this can cause the mirror to be completely out of alignment. 

However, if all 3 adjustment screws are very tight, the central locking screw can be loosened very gently with a Phillips screwdriver. However, it is always safer to loosen only one of the locking screws to allow the other two to move freely.

Misaligned Secondary Mirror

  • Use the4mm Allen wrench on the 3 push/pull adjustment screws to move the black spot to the center.
  • When finished , carefully retighten the center screw if necessary.

Well Aligned Secondary Mirror

When the adjustment is complete, the black dot should be right in the center of the red circle.


When finished, carefully try to retighten the center screw if necessary. Check that the mirror is still in place.

Next Step

Step 4: Adjusting the Primary Mirror

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