First post! Collimation Question

[cavelltodd]

Hello everybody! It's nice to find another great forum for amature astronomers!

Recently I disassembled my Meade 12" Lightbridge to clean it up. After putting it all back together I am having trouble with the collimation. I have it pretty close but I'm not 100% sure how to tell if what I am seeing is correct.

I've gone over astrobaby's tutorial and several others to help me get this figured out. Although the tutorials make perfect sense and I know what has to be done I can't quite get everything tightly together.

I am using a combination of a 35mm film canister collimation cap and a celestron cheshire eyepiece.

First of all, when centering the secondary mirror directly under the focuser I can't raise the mirror up enough towards the spider vanes to get it centered. I simply just run out of room and the secondary ends up right against the bottom of the spider. Ok, so I get it close enough and try and make do.

Next when aligning the secondary to the primary I get the primary centered just fine in the secondary and it all looks good. I then insert the cheshire and when I look through the eyepiece the secondary mirror is too far down the tube to be centered below the cheshire. I see a small crescent of black (the secondary mirror housing on one side of the cheshire and then the mirror goes beyong the opposite side of the cheshire. Ok, so I make do.

Next I align the primary mirror so that the center mark on the mirror is in the middle of the reflection with the dark spot that the cheshire creates and when I get these two lined up nothing is centered with the crosshairs. Everything is centered with the reflective part of the cheshire but not with the crosshairs.

Then I take out the cheshire and put re-insert the 35mm collimation tool to check the finished product and it all looks ok...maybe I'm not sure...but I'm just not sure if it is really collimated. The main thing I notice is that, although everything seems centered well, the reflection of the bottom of the focuser is off center of the secondary mirror. When I check my users manual it says that the secondary mirror needs an offset of 1/8" in both directions and I am assuming this is built in to the telescope. The pictures they give of a good collimation look similar to what I have but my offset looks much more dramatic than what they show.

Here's a picture of the final product of my collimation. I took it through the 35mm collimation tool so the quality isn't the greatest but I think you can get the idea of what I am talking about.

Sorry for such a long winded post but I have a lot of questions that I just haven't been able to find answers to after a couple weeks of searching the internet. Who knows...maybe someone will have the same questions as me one day and be able to find the answers right here in this post! haha

Anyway, thanks in advance for all your help!