Actual Step

Step 4b: Primary Mirror Collimation using OCAL

updated: 2024-05-18

Purpose

Aligning the primary mirror with the optical axis of the telescope

Previous Step

Step 2b: 2nd Mirror Collimation using OCA

Next Step

3 alternative follow-up steps:

  1. Step 2: Re-check and correct mirror spacing 
  2. Step 3b: Re-check 2nd mirror collimation using OCAL
  3. Step 5: Fine Adjustment of the Primary 


Steps



  • If possible remove the internal baffle on the main mirror that blocks obliquely incident light (this is possible e.g. on the TSO 203/1624 RC PRO)
  • Slightly untighten den locking screws on the backside of the mirror using a 2.5mm Allen key
  • Next, switch on the collimator in Newtonian/reflector mode (red LEDs)

Activate the blue circle in the OCAL App

Misaligned Primary Mirror

  • The blue circle should evenly surround the shaft of the secondary mirror.
  • Now you center the blue circle by adjusting the primary mirror using a 3 mm Allen keys on the silver push/pull screws.
  • It is recommended that the "B" screw be maintained in its current state, thus maintaining the mirror in its current position and changes in mirror spacing are avoided.

Well Aligned Primary Mirror


  • The result at the end of this second and last step of the collimation should look like this. Collimation is finished and the telescope is ready for the night.

Finalization
  • Re tighten the locking screws slightly to prevents that the pressure on the cell gets too strong or that the mirror position remains unstable.
  • Re-install the internal baffle on the main mirror.

Next Steps

3 alternative follow-up steps:

  1. Step 2: Re-check and correct mirror spacing 
  2. Step 3b: Re-check 2nd mirror collimation using OCAL
  3. Step 5: Fine Adjustment of the Primary 

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