Laser Collimators

[Damo636]

I have replaced the metal washer i originally placed between the secondary mirror holder and the adjustment screws with the milk carton washers (as per Jason's diagram) and can confirm they work a treat.

[earth titan]

Cheap Meade here. Inside is a cheap laser pointer with button cells.

Once 'collimated' I use it for aligning the secondary until the laser dot falls nicely on the primary centre spot, then pop the laser in a barlow to align the primary. Seems to work for me.

[Dipper]

Once 'collimated' I use it for aligning the secondary until the laser dot falls nicely on the primary centre spot, then pop the laser in a barlow to align the primary. Seems to work for me.

I've read that a few times. What exactly is the effect of a barlow'ed laser collimator beam?

[earth titan]

A barlowed laser gets rid of the slop etc. in the finder. Means you then have a perfect collimated laser and you can do a really tight collimation of the primary.

For a better description, read this article:

http://www.cameraconcepts.com/barlowed%20laser%20collimation.pdf

[Dipper]

Thanks a lot!

[earth titan]

No worries. Any questions, drop me a PM.

This method really works for me. It's a site cheaper than an expensive labour and from the research I've done, as accurate as any other method - if not more so.

[Jason D]

Means you then have a perfect collimated laser

Barlowed laser does not transform a low-quality laser collimator to a high one. If that was true then all high-end laser collimator manufacturers would have been out of business.

With laser collimators, the first step is to align the secondary mirror to center the forward laser beam against the primary center spot. The second step being adjusting the primary mirror until the returned beam retraces its forward path. Any errors in the first step will impact the second step when the unbarlowed laser method is used. The barlowed laser method isolates the two steps. It does not solve issues with the first step but rather prevents errors in the first step to impact the second step.

Jason