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Should the crosshairs on the cheshire overlap the reflected ones in the mirror then?

Eventually, when axial collimation is completely correct, yes.

The centre spot reflection is blurry on that picture, and I don't think it's concentric with the Cheshire ring reflection just yet (i.e., I don't think the primary tilt is set correctly yet.) Could you try to take a picture with the camera with the f/ratio set a bit "slower" on the camera lens, if possible, so that there's more depth of field, and with the centre spot illuminated separately?

Edited by sixela
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So it close but not just there i have given it my best today but just can`t seem to get the cross lined up on that one :).

Could the focuser be out of line slightly as when the cheshire is rotated the cross stays the same .

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For setting primary tilt, dont use the cross-hairs. Use the Cheshire ring and make the centre spot reflection concentric with the Cheshire ring reflection. Or use a collimation cap and make its pupil reflection concentric with the centre spot reflection.

Use the cross-hairs vs. cross-hair reflection only as a final check.

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...I always keep the French proverb in mind, "Le mieux est souvent l'ennemi du bien" or "you can drive yourself crazy striving for perfection in areas where the incremental benefit is less than the work required to achieve it." French is such a compact language.

Cool proverb, I'll have to remember that although it's a shame I'm unable to pronounce it! :)

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Then if that's concentric with your Cheshire ring round it, you're done. Well, there is still a bit of rotational error corrected with tilt (the offset between the Cheshire ring and the silhouette of the secondary's reflection is not away from the focuser, which means that the secondary is tilted a bit clockwise in that view), but you can simply leave that alone for the time being. It has few practical effects, not even on the fully illuminated field.

What I'm finding a bit strange, though, is that you can't see the whole of the primary even though the focuser draw tube already impinges on the primary reflection. That secondary looks a bit undersized, or the draw tube a bit long. But that's not a collimation issue.

Edited by sixela
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