Quote:
Originally Posted by Cluster
Today I received a GSO laser collimator for my GSO 6" reflector. I've turned it on and did a simple roll test (roll across the end of a desk) and it seems to be in a straight line. I'll do a V wedge test later. Turning the collimator in the focus tube shows a tiny deviation from dead center (about 1 or 2 mm on the primary mirror).
The main question is, the laser doesn't come to a point when shone on the wall. At about 2 metres away it's a slit about 4mm wide. On my telescope's primary mirror it's very difficult to tell if it's in the center of the mirror as the laser is so broad. I think I have achieved collimation of the primary and secondary as the return laser beam is bang on target in the collimator.
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Yes, my experience is that these cheap red lasers (pointers etc.) do generate an elongated spot rather than a round spot. 4mm at 2m sounds a bit on the larger size.
Quote:
Originally Posted by Cluster
When I pointed the laser collimator through my GSO 3x ED barlow, collimation was a bit off but not too bad (in my opinion). Is the laser point (it was pretty large, about 2cm across) meant to be dead bang in the center of the primary mirror?
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Did you mean you used a barlowed laser to check collimation? With a 3x barlow, i've seen quite a large elongated spot - several cm across - more than 2cm. "dead bang in the centre"? Well, no, in fact if you wobble the laser in the focusser, the diffuse spot will move all over the primary. But this is the object of using a barlowed laser. While the spot moves on the primary, the shadow reflection of the centre spot (paper ring donut or triangle or whatever you have stuck on your primary) back at the laser does not move.
Quote:
Originally Posted by Cluster
Do the three Allen key holes in the GSO collimator just move the beam, or do they adjust the focus of the beam itself?
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Not in my experience, they just adjust the direction of the beam BUT as you move it, the beam can begin to clip on the edge of the hole it is exiting so you may see the projected shape change due to that. But at that point, the beam is probably not aligned with the mechanical axis, anyway.
Eric
