If you have a new account but are having problems posting or verifying your account, please email us on hello@boards.ie for help. Thanks :)

Hello all! Please ensure that you are posting a new thread or question in the appropriate forum. The Feedback forum is overwhelmed with questions that are having to be moved elsewhere. If you need help to verify your account contact hello@boards.ie

Hi there,
There is an issue with role permissions that is being worked on at the moment.
If you are having trouble with access or permissions on regional forums please post here to get access: https://www.boards.ie/discussion/2058365403/you-do-not-have-permission-for-that#latest

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…

18-06-2010 7:51am

#1

peterako

Registered Users, Registered Users 2 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

0