CENTRAL PUPIL
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Using the central pupil only:
Adjust only the secondary mirror until reflections "P" and "3" stack forming a prefect hexagram -- an indication of FAE elimination.
| OFFSET PUPIL
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| Stacking reflections "P" and "3" via the central pupil based on CDP eliminates FAE
STEP 4: Eliminating PAE by adjusting the primary mirror:
Remove the INFINITY XLKPTM autocollimator and replace it with the BLACKCAT XL-ATM Cheshire (or similar PAE alignment tool).
Adjust only the primary mirror until Reflection "P" is perfectly centered in the cheshire ring.
CHESHIRE VIEW
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Centering reflection "P" using the Cheshire (or similar PAE alignment tool) eliminates PAE
STEP 5: Checking for residual errors:
CENTRAL PUPIL
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Re-insert the INFINITY XLKTM and check reflections via both pupils.
If your see residual background ghosts via the CENTRAL PUPIL and/or imperfect hexagram via the OFFSET PUPIL then you have residual axial alignment errors.
OFFSET PUPIL
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STEP 6: Correcting potential residual errors:
CENTRAL PUPIL
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Repeat the CDP (step2) with more precision by ensuring reflections "P" and "3" form a perfect hexagram in the CENTRAL pupil and redo steps 3 - 5.
After carefully repeating steps 2 - 5, ensure only reflection "P" is visible in the CENTRAL pupil and perfect hexagrams appear in the OFFSET pupil.
OFFSET PUPIL
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Re-check for PAE elimination using the BLACKCAT XL-ATM Cheshire (or similar PAE alignment tool).
STEP 7: If errors still persist, try this iterative adjustment approach:
Using the CENTRAL pupil, eliminate all inverted background ghost reflections with only "P" remaining by only adjusting THE PRIMARY MIRROR.
Using the OFFSET pupil stack reflections "P" and "2" to form a perfect hexagram by only adjusting the THE SECONDARY MIRROR.
Iterate back and forth betweeen adjustments of the two mirrors as necessary; usually 4 or less iterations is required.
Successful Axial Convergence and What it Means!
If "all" tools simultaneously yield "textbook" visual queues, optical axes convergence has been accomplished. With sustainment of these adjustment settings, you can be confident that your scope will perform to its maximum image-detail-delivering potential that atmospheric "seeing" will allow.
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