Ik was mij helemaal niet bewust van het feit dat dit soort telescopen nog zoveel collimatie nodig hadden. Dat was toch juist een voordeel van lenzen-kijkers, dat dat eigenlijk niet nodig is (althans, niet als het al goed staat)? Ik las dit in een oude post op CN:
“So then the problem with a scope like my Orion ED 100, the ED 80 or the Orion ST120 and a variety of other scopes is that failing the built in ability to align the primary optics, really good collimation is quite difficult. An adjustment of the focuser end of the tube assembly cannot really be used to collimate a scope perfectly unless the primary optics are in a cell that is in perfect alignment with the tube and the problem is only at the focuser end. The reason being that the light cone of misaligned optics will not line up with the center of the tube and adjusting the focuser cannot rectify this as the optical axis of the focuser and the optical axis of the optics will always meet at an angle. This was a problem inherent in long focal length large refractors of the 19th century as tube generally could not be made as true and as straight as today. Additionally their sheer weight coupled with long length caused some sag. This is why those tubes had to have considerable reinforcement; basically to prevent sag that would greatly affect collimation. So unless you 1) offset the focuser, and then 2)bring the focuser’s optical axis in alignment with the optical light cone there is no way to really collimate a scope well from the focuser end if the optical end is the real problem.
I feel that you can improve collimation somewhat, but without the ability to easily collimate from the optics end too, it cannot really be done well in any scope that does not give one this ability. You could shim the objective in it’s cell, but this would be a slow process. If well machined, the optics end should be ok, but if the threads for cell attachment are not cut square to the tube, we are both literally and figuratively “screwed”. One of the first things to check would be to verify that the cell is not cross-threaded onto the tube.”
Kan je dus eigenlijk wel een goede collimatie met deze refractor krijgen zelf?