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Help - How to correctly collimate a Newtonian... with a twist

Started by RobertM, Nov 08, 2011, 10:44:03

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The Thing

Quote from: MarkS on Feb 01, 2012, 09:02:30
Assuming it's clear tonight I intend to tackle my C11 reducer problem again - this time with a tilting adapter.

Hi Mark, bit of a hijack but... I found that collimating my secondary with the mirror a little way down the collimating screws, ie: not tight to the stops, made my collimation much much better in the corners. I suspect that the secondary mount plate distorts slightly if any of the screws are tight rather than balanced on the springs and relying on the springs to keep the secondary collimated. I read recently of a guy who put an extra spring in the middle of the secondary (the plate sits on a central post) and that helped make it easier to get a good result as well.
We're all guinea pigs in the laboratory of life. Better a fluffy guinea pig than a lab rat!
¯\_(ツ)_/¯ (Gallic shrug :))

RobertM

The C11 doesn't work like that.  The three collimation screws act on a thick plate over a central fulcrum pin so they have to be relatively tight.

Robert

The Thing

Quote from: RobertM on Feb 01, 2012, 15:35:53
The C11 doesn't work like that.  The three collimation screws act on a thick plate over a central fulcrum pin so they have to be relatively tight.

Robert
Exactly the same in the LX90, but in the LX90 the springs keep things in the set position.
We're all guinea pigs in the laboratory of life. Better a fluffy guinea pig than a lab rat!
¯\_(ツ)_/¯ (Gallic shrug :))

MarkS

Quote from: MarkS
Assuming it's clear tonight I intend to tackle my C11 reducer problem again - this time with a tilting adapter.

Rats!  It's clear but far too windy tonight.

Mike

Yeah I was hoping to test out the D7000 tonight as the adapter arrived today but its way too blustery to get anything decent. Plus the moon is pretty bright which also doesn't help.
We live in a society exquisitely dependent on science and technology, in which hardly anyone knows anything about science and technology. Carl Sagan