collimating a collimating laser?

[troypiggo]

Being new to all things Newtonian, I've been doing reading on collimation. Also got some handy tips from Rider when I picked up Argyle[1]

In terms of these laser collimators, I've read that they themselves have to be collimated. I have this Orion LaserMate Deluxe Collimator (https://www.bintelshop.com.au/Product.aspx?ID=8108) from Bintel. It doesn't appear to have any features that allow it to be collimated itself. How likely is it that there will be an issue? How do I test if it needs collimation, or if it's "off"?

I believe that to supplement the laser type one like the above, it's a good idea to get a Cheshire type one. Would this one be similar or achieve the same thing (https://www.bintelshop.com.au/Product.aspx?ID=5508)? Any other suggestions?

I've read the "how to" in the IIS articles section, but that's about it so far.

[1] The name of his, and now mine, 10" SW Black Diamond Newtonian OTA :)

[adman]

To test whether it needs collimating itself - stick it in the focuser and look down the tube to see where the red dot lands on the primary. Then rotate the laser in the focuser through 360 degrees. If it is ok, then the dot should stay in the same place, if its not OK, the dot will rotate in a small circle as you turn the laser in the focuser.

or you can try this method: http://www.cloudynights.com/item.php?item_id=520

I think that the orion one does have three collimating screws, but their holes are covered with some kind of waxy/plasticky material, and I think one of the holes is under the 'don't-shine-this-in-your-eye' sticker.

Adam

[troypiggo]

Aah, of course. Thanks for that. Seems so obvious, I feel silly.

[mercedes_sl1970]

Troy

Here's another jig that is very easy to make: http://www.stark-labs.com/craig/llcc/llcc.html.

I made one myself recently after the collimator I bought was obviously out. About 1 minute to make and about 10 minutes to fix the collimation.

Andrew

[erick]

Just one small problem. It cannot be guaranteed that the contact points on the rear of the laser collimator are concentric with the laser axis. They may be, but they may not. I suspect most will be close enough.

To step up a notch, the laser should be gripped by the front barrel only and rotated there. If you have a lathe, easy. If not, here is a fancier tool that will do the job:-

http://www.iceinspace.com.au/forum/showthread.php?t=39108

Come to Snake Valley camp in November and we'll test your laser :D

But I'm sure you get the idea and can think of an approach that achieves this ideal.

[monoxide]

i adjusted mine using a 2" to 1.25" adapter in a vice with the laser spot against the shed wall 2 - 3m away.

[troypiggo]

All great ideas, thanks guys.