Laser Collimators - worth the hassles?

[pmrid]

AFter a disappointing outing with a GSO laser, I decided to spend up big and bought one of those Baader numbers where the beam is reflected back and displays on a semi-translucent screen - when the dot goes back through the same hole it goes out by, you're there.
The laser sits in a standard 2" adapter in the drawtube - held by a 3-screw compression ring. Seems quite firm etc etc.
Trouble is, that if you just spin the laser in the 2" adpeter and watch the dot on the primary, it scribes a circle several inches in diameter. SO the idea of using the laser to align the secodary as a first step to collimation is a flamin' joke.
OK. The Laser itself needs to be collimated - is that it?
Holy mackerel, I am sooooo over paying good money for stuff that doesn't do it's job.
I have made a simple Barlowed Laser so I can use the centre-spot shadow to collimate the primary but the accuracy of that method depends entirely on getting the secondary right first.
SO we come back to this - how the dickens do you collimate a laser?

Peter

[allan gould]

Peter
I had A vixen VC200L and there were several ways to collimate it. Vixen stated that the BEST way way to do a series of steps visually starting with the primary mirror etc. I thought I could do better with a laser but to be honest although I paid top dollar for it it was not concentric in the barrel and no amount of shiming made it really accurate.
I went back to the visual method and nailed it with Vixens explicit instructions. For some systems like a Newtonian that's tried and true a laser is excellent but a complicated compound system forget it as the eye is more accurate as long as the manufacturer has defined a set of steps to follow.
Just my 2c and I sold the laser.

[brian nordstrom]

:) Hi Peter I have never owned a laser , but every Newtonion and CAT I have collumated I use the concentric allignment of the primary , secondary and draw tube method , then the unfocused star test .:thumbsup:
I dont think you can do better than that and its a whole lot cheeper .
Brian.

[Shiraz]

Hi Peter. Alexander posted a good summary of a method for collimating a GSO laser - should be applicable to others. In general, have found that a properly set up laser can do a pretty good job of collimating both mirrors - easy to then tweak the primary on an unfocused star as Brian points out. Regards Ray

http://www.iceinspace.com.au/forum/showthread.php?t=75601&highlight=collimator+laser

[pmrid]

Thanks for that Ray.
Peter

[erick]

Answer - Yes.

For most reflectors, a well-collimated laser is a great tool to get very quick "good enough" collimation. I say "most" cause I'm really not sure with these faster mirrors (sub f3.5).

Getting your laser collimated? Either buy one from Howie Glatter since his promise of it being collimated and never losing collimation even if you drop it seems to be people's experience that I have read. Or buy something else and adjust the collimation yourself. Most can be easily done. The GSOs are easy (once you remove the stupid second o-ring they put in place (cannot find the sheet of information I have on this, sorry. It is somewhere on IIS, back about 3 years. And on my hard drive, somewhere).

Here is what I use:

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

I carry it to Star Camps so if you see me there, we can check out your laser. I am thinking about showing up at Astrofest this year :driving: