Collimating a 12.5 F5 Newtonian

I currently use a Helix laser collimator for setting up my scope. I have read about Chesire collimators, but have not used one. Can anyone offer some advice as to what they use and how happy they are with the results.

I'm curious as to whether or not this is adequate, or if there are easier, more efficient or more precise methods.

Thanks,
Chas

There was a long thread recently where the Cheshire and laser disagreed. Sir Isaac never had a laser ;-)

Matt

A cheshire enables you to align all elements of the visual path, including the focuser with the secondary, the secondary with the primary, and the centering of the primary. A laser collimator can enable the latter, aligning the return of the center dot back to the collimator in the focuser, but it does not address the focuser/secondary alignment or secondary/primary alignment. You can have a systematic alignment error in those with no indication, using a laser collimator alone.

I use a cheshire to perform all alignments visually, then verify the collimation with the laser. This is on an 18" f/4.5 system. If they disagree, I'll go thru the process a second time until the results using both the cheshire and the laser are close. I don't insist that the laser be dead-centered on the center dot of the primary. Through experience, when the results vary a bit, I've learned to trust the cheshire more.

Good luck,
Howard

Chas,

For what it's worth, I use the three pieces that Tom Clark made: the cheshire, the sight tube, and autocollimator. I've found that I get better images using these three than the laser (I've borrowed a couple over the years).

Clear Skies,

guy
12.5" f/6 dob