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Collimation Problem....

peterako · 2010-06-18 07:51:29

Hello all, I have upgraded to an 8" Newtonian. It's a Celestron G-8N...so strictly speaking it's a Newtonian with a lens in between the Primary and Secondary. I am encountering something unusual when I do a Star test. I can get almost perfect collumation either intra focus OR extra focus but not BOTH at the same…

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18-06-2010 8:51am

#1

peterako

Registered Users Posts: 720 ✭✭✭

Join Date: August 2007

Posts: 686

Hello all,

I have upgraded to an 8" Newtonian.

It's a Celestron G-8N...so strictly speaking it's a Newtonian with a lens in between the Primary and Secondary.

I am encountering something unusual when I do a Star test.

I can get almost perfect collumation either intra focus OR extra focus but not BOTH at the same adjustment.

If I set one side of the focus nicely the other side of the focus invariably is coma offset.

Sort of like this:

Any tips/suggestions?

Thanks in advance,
Peter

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