Collimating the Dob, again

October 11, 2026

After moving the scope in the car the star test showed a clearly off-centre shadow. Steps that worked:

1. Centre the secondary under the focuser with the Cheshire.
2. Adjust the secondary tilt until the laser hits the primary centre mark.
3. Use the Barlowed laser to set the primary; much less sensitive to a slightly tilted focuser.
4. Final check: defocused star at high power.

Total time about twenty minutes. Rings were concentric afterwards.