Cheshire crosshairs

[Pete D]

I tried that but when I rotate the mirror I cannot get all 3 clips in view and the back of the secondary is at a angle (3 screws uneven)

[Moonshane]

when you rotate the secondary you don't touch the three tilt adjusters other than to loosen them enough to allow the secondary to turn. if sending the secondary down the tube a little (which it needs) you would need to loosen the central bolt and then tighten up the three tilt adjusters equally to take up the slack.

[Pete D]

When I turn the secondary it alters the tilt more than the actual postion of the mirror, not enough anyway.

[Scooot]

Yes I agree with Shane that's what I ended up doing. Block out the primary with a piece of card so you can just see the secondary. Then rotate the secondary slightly, it will be a very tiny turn, until you can see it filling the view in the cheshire, look through the cheshire to check you can see all the secondary once you've done it. It might appear a slightly oval shape at this stage. When you remove the card you'll see an obscure primary, maybe only 2/3 of the mirror. At this stage you adjust the the 3 secondary screws to bring the secondary crosshairs into the middle. If you then put the card back in place to look at the secondary it will appear round.

[Scooot]

Ps I think you need a slight clockwise turn.

[Pete D]

I shall give it a try tomorrow. Was you able to see all 3 clips with the crosshairs in the middle. I seem to be able to get the clips or the crosshairs right not both. Thankyou all.

[Scooot]

The first thing is to centre your mirror in the focuser, don't worry about clips at this stage. So block out the primary so you can only see the secondary. As Shane observed it looks as if it needs to move down slightly, but if you look through the cheshire you can tell, you want the cheshire to encircle the secondary as best you can. If its slightly to one side, which it looks like, you need to rotate it around the central bolt very slightly. You might need to pull the cheshire out etc to judge. As mentioned the secondary might appear oval at this stage because it's not aligned with the primary. When you remove the card and look at the primary you'll think wtf. Then use the three adjusters so you can see the primary clips and all the hard works done.

[Moonshane]

if you trust the process and go through it from start to finish you'll get there in the end. understanding what you are seeing is half the battle.