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Old 08-12-2011, 01:31 PM
clive milne
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clive milne is offline
 
Join Date: May 2011
Location: Freo WA
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Quote:
Originally Posted by Poita View Post
As stated by others, there is no need to collimate, it should be nice and square from the factory and stay that way for ever.
In theory yes, but that is not always the case (even from high end manufacturers like AP) and it does depend on how the lens cell is attached to the tube.

As Andrew suggested, putting a cheshire in the focuser will show you in an instant (obviously the dust cap on the front of the objective should be on when this is done)

Generally speaking though, field aberrations in refractors are well controlled so the collimation has to be a fair bit off for it to be a problem. The caveat to this of course is in designs which have multiple lens groups.
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