quick collimation screw question.

[EzyStyles (Eric)]

Hi,

Just a quick question. To move the pirmary mirror further away from the focuser (back), its it clockwise or anti-clockwise on the collimation screw?

The problem is i can't seem to get focuse now after taking my primary mirror and secondary mirror out .

Thanks.

[rmcpb (Rob)]

Screw 'em in!! Clockwise will pull the cell toward the back of the tube.

[EzyStyles (Eric)]

thanks rob. silly me heheh

[EzyStyles (Eric)]

forgot to ask, does it matter on the number of rotations from the collmation screws? eg: 2 screws are turned 4 times whereas 1 screw turned once (the screw parallel to the focuser).

[ving (David)]

colimated is collimated eric
the primary is sitting flat in its cell isnt it?

[RAJAH235]

Eric, Please start by screwing all of them right down, till they bottom out, then BACK OFF 1 1/2 to 2 turns. (I say this to get as much tension on your springs as poss).
Provided the cell etc is manufactured acurately, the light path will be reasonably close to correct. (Know what I mean)?
From there, go step by step thru your collimation procedure again, starting with the centering of the focuser in the tube, the 2ndary in the centre of the focuser, (using a sheet of white paper on the opposite side of the tube to see what's going on), etc etc.
Just take your time with it..
HTH. L.

[EzyStyles (Eric)]

Originally Posted by ving

colimated is collimated eric
the primary is sitting flat in its cell isnt it?

I believe so.. but why does that one of the collimation screw is less turn than others? *shrugs*

[EzyStyles (Eric)]

Originally Posted by RAJAH235

Eric, Please start by screwing all of them right down, till they bottom out, then BACK OFF 1 1/2 to 2 turns. (I say this to get as much tension on your springs as poss).
Provided the cell etc is manufactured acurately, the light path will be reasonably close to correct. (Know what I mean)?
From there, go step by step thru your collimation procedure again, starting with the centering of the focuser in the tube, the 2ndary in the centre of the focuser, (using a sheet of white paper on the opposite side of the tube to see what's going on), etc etc.
Just take your time with it..
HTH. L.

thanks for your reply. I have turned all 3 screws all the way down. I use a laser to collimate my primary mirror. 2 screws seem to be evenly turned while only one takes less turn . weirdd. thanks for the idea of the white sheet. i'll try that.

[RAJAH235]

Eric, You're welcome. Tell me tho, you did back them off ~2 turns after bottoming them? Need to do this to get some 'room to move' the mirror cell.
The reason for the screws not being turned equally, is simply a cell design/manufacturing tolerance issue. Nothing is perfect.
Glad to be of assistance.
Regards, L.
ps. Oh, it helps if you collimate in the daytime too. Can see things clearer. Just point the tube towards an open door or window.(Nice even light source).