Laser Collimation Question

[Waxing_Gibbous]

I have to admit that I had, until today, never collimated a Newt. Judging by the number of posts on different forums, this practice seems to be particularly difficult and occupy a good deal of what would otherwise be productive observing time.
Last week I bit the bullet and purchased an Orion LaserMate as my 8" was hopelessly out of wack.
I read and re-read the instructions, did a "dry-run" to familiarize myself with the instrument, loaded up with tools and settled-in for a long afternoon of fiddling and frustration.
About 8 seconds later, I was all done.
A brief opening in the clouds ten minutes ago revealed perfect stars with only minor coma in the outer 10%.
Did I screw-up somewhere?
I'm sure this is supposed to take hours?
Books have been written about it.
If I was into AP, I suppose I could have fine-tuned it an extra 1/10 mm or so, but it seems to be working fine.
I must've buggered it somewhere, but I can't think where?:D
Suggestions welcome!

[wavelandscott]

While you did not outline the process/procedure that you used, collimation itself is not difficult once you understand what is happening (or suppossed to happen).

It is something that a refelctor owner should check before each use to ensure that you get the best view possible.

[Robh]

Well done!
I think with collimation you just have to bite the bullet first time and do it.
Collimating with a laser collimator is a simple procedure:
1. center the laser on the primary by adjusting the secondary.
2. center the return beam in the collimator by adjusting the primary.
For most, this is usually good enough!

If you use a cheshire collimator as well (step 3) to fine tune, the procedure is a little more complex but none-the-less fairly straightforward. Explaining the procedure is more difficult then the doing.

Coma to the outer field is an inherent problem with fast mirrors at low powers and won't be solved by collimation.

Regards, Rob.

[Dave47tuc]

Hi Peter,
My personal opinion is the web has over complicated the whole collimation of a Newtonian, with one thread after another about it. Some go into so much depth it makes me laugh.
With your ex newt, and you gave me a good tool to start with, but I also purchased a astro-systems Barlowed laser collimator. I have found this device so easy to use its not funny.

What I found ridiculous was at so many nights out viewing with others and so many observers blamed one thing or another on why they could not get a sharp image. When it all just came down to simple collimation.
And there comments where
"but I read how to do it on the net but all it did was confuse me"
I must admit i confused myself at times:confused2:
But really its not hard even in a SCT.
You seem to have got it and found hey it really is easy ;)

[Starkler]

Couldnt agree more. The basic principals of what we are trying to achieve are really very simple. The confusing part can be relating what we see with our tools in trying to achieve that goal.

FWIW, a cheap laser is not a total collimation solution and on its own does not guarantee accurate collimation or even do anything for secondary placement at all, only its tilt.



Indeed. Once collimation has been done thoroughly once, its usually just a minor tweak of the primary on each use to keep things spot on;)

[Kevnool]

Also try putting the laser into the focuser then move the focuser up and down whilst doing this observe the laser dot on the primary mirror and it moves then the focuser is not squared to the tube.

Cheers Kev.

[Waxing_Gibbous]

Hey guys,
Thanks for that. The instructions that came with the Lasermate are fairly comprehensive and I've gone through all the steps you mention plus a few from websites and books. I was simply surprised at how easy it is.
From all I've read, I was expecting it to be a thouroughly complex process, the laser tool obviously helped, but, really its nothing to be afraid of, and much easier than collimating a triplet refractor.
I suspect a long FL SCT or Mak would also require a softer touch and more precise placement, but still, not Rocket Science, as they say.
So to anyone who feels a little overwhelmed by the prospect of trying this the first time, I say: just have a go! I'm very probably one of the most cack-handed people on earth, and if I can do it, so can you!
Cheers!
Peter

[bobson]

When I had my Skywatcher 8" dob I never had to collimate it. Even when I took mirror out to wash it I just marked the cell and put it back and after checking collimation was spot on. Bigger Dobs like my Bintel 12" tend to go out of collimation more often, but if you invest into stronger springs then miner corrections are needed only if you drive over rough roads :)

Check if the laser collimator is collimated itself first by putting it in two V shaped peaces of wood. You can find instructions here on this forum. Put it about 5 meters away from the wall or something, ask someone to turn it around and see if the dot makes circles or stays still. It should stay still, if not your laser collimator needs to be adjusted/collimated.

My laser collimator from Andrews was totally out when I received it, and it took me a while to adjust it before it could be used.

Try Barlowed laser collimation, you can really fine tune this way.


bob

[erick]

Yep, nothin' to it to get to "good enough"! :thumbsup: