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Let me say something about collimation and newtonians...
I've only ever owned newtonians, bought the first one in about 1990, and I've designed and built two more up to the present.
Nowadays I'm quite happy with collimation, and I don't find it intimidating any more but for a long time I found collimation very puzzling. It seemed to me that it should be a simple idea (align this mirror with that, centre this in the focusser, etc ) but whenever I tried these simple things I always ended up with some parts of the system that weren't concentric, and most times I came away with more questions in my mind about whether or not I was doing the right thing.
This is the sort of confusion I see in other people as well, puzzlement that such a simple-sounding idea can be tricky to do in practice.
My $0.02 worth is that the basic problem comes from the wrong assumption that collimation is simple to understand and do without really paying attention. Just having this idea in your head means that you'll more than likely do things in the wrong order, or not understand which reflections should be concentric and which ones shouldn't.
Let me say this - collimation *is* easy, provided that you do things in the right order *and* you understand about secondary offset (whether or not you choose to do it) and what reflections should be concentric with the focusser and which ones shouldn't.
Just doing *one* thing out of order when collimating will invalidate the whole process and more than likely end up with a scope performing badly. Collimation is a sequential process with lots of steps (if you're starting from the beginning) and you absolutely have to do them in the right order.
If you haven't yet taken the time to learn these two important things about colimation then you're doomed to forever go in circles without really knowing what you're doing. I was like that for many years until I finally got fed up with it and knuckled down to understand what I was supposed to be doing.
As far as I'm concerned everyone who wants to collimate a newtonian should have a copy of Vic Menards book on collimation (co-authored by Tippy D'Auria) called "New Perspectives on Newtonian Collimation", it's a small paperback, google for it and you'll find it. It's cheap and well worth it.
There are also many websites around that explain both the theory and practice of collimation, with pictures to show what you should be seeing. Yes, they can seem confusing, but print them out and leave them where you can keep looking at them and sooner or later the light will go on.
If you own a newtonian then you really have to understand how to collimate it, otherwise you'll be forever stuck with poor images until you trade it in for a refractor :-)
regards, Bird
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