primary mirror clips.

[rory]

i flocked the area around the mirror the other day and its all back togeather and views are fine. but ive a niggle at the back of my mind. when i placed the primary back and placed the three clips back on with two screws on each clip,im sure i did them up reasonably tight. not over the top but secure shall we say. trouble is i cant recall how tight they were when i dismantled it ? should the clips be just touching the mirror , not at all ,or securely ?

thanks .

[BAZ Senior]

The mirror clips should not be tight at all, if they are even slightly tight, you will get triangle shaped stars and it will not show a good image.

I was informed by a regarded scope maker, that the mirror should be free to move, not sloppy, but able to rotate by hand.

I got some of the brown baking parchment, which is fifteen thou' thick and tightened the screws down to it, and then slackened them off until I could move the parchment under the clips, without it being trapped. This gives a clearance, without it letting the mirror move back and forward.

If you have triangle stars, it's to tight, that was the problem I had after taking the mirror out for a clean.

Hope that helps.

[rory]

thanks baz. my niggle was justified by the look of it then. shall sort it now.

[sgazer]

I nearly had heart failure when I tried that on my dob, I tightened the screws only a bit and all my stars looked like triangles, didn't know why at the time. I had to adjust them so they were barely holding the mirror before it was ok.