Chishire centering in secondary. Please help

[pat]

1) Looking down the peep sight tube, the chishire "annulus" is not exactly centered in the middle of the secondary mirror (you can see that the position is downwards).

2) The black dot is centered in the donut hole.

I was told I could adjust the primary mirror to center it, without disturbing the black dot in the donut hole.

I twicked one adjustment bolt on the primary and the black dot

moved.

As a side note: I wanted to completly darken the inside area of my "Auto-Collinator". A forum member suggested I adjust the secondary screws. Maybe if I get the AC dark, I can forget about centering the chishire "annulus". Pat

Too many stars too little time**************

[Nova]

moving the primary mirror will always move the dot (by dot i assume you mean the reflection of the eye hole?) when adjusting the secondary you need to ignore the donut reflection and concentrate on getting all the clips of the primary visible and ensure the the secondary is presenting as a nice circle. when you have achieved this then move onto adjusting the primary so the anulus, cross hairs and donut all align. google "astrobabys collimation guide" (sorry cant post link from my phone) its a huge help! with practice you will get thw hang of it

[pat]

Thanks, With this information I'll be getting closer to collimation. Forgot to say in my post, that my chishire does not have crosshairs. Pat

[nicnac]

Astro Babys Guide to Collimation

hope this link helps

[Nova]

it is quite a daunting process at first. im over the fear of doing it now but still dont think ive got it perfect but im happy with the results i get so im not sure if 100% perfection is totally nessercery

[nicnac]

agreed

just come across this vid that one of the other members found

Collimating a Newtonian