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Old 21-10-2013, 11:55 AM
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Jason D (Jason)
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Join Date: Aug 2009
Location: California USA
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Quote:
Originally Posted by ausastronomer View Post
Hi Jason,

While that is fine in theory; and in fact in practice, in terms of telescope performance, there are other things to consider. The main one being that most people that spend somewhere between $10,000 and $100,000 on a custom built truss dob don't understand the optical theory behind collimation and they don't look at collimation ray trace diagrams. They just expect everything to be squared, properly symmetrical and properly aligned and positioned. The fact that it doesn't matter in practice in terms of telescope performance, is totally academic to them. In this regard a well collimated laser does a good job of squaring the focuser and positioning the secondary when the Upper Cage Assembly is initially being set up for the first time.

Cheers,
John B
John, it is the other way around. In my last post, I was advocating for a simple and a practical collimation method.
A laser does do a good job is squaring the focuser but it does not do a good job in positioning the secondary mirror under the focuser -- unless it has a holographic attachment.
Jason
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