Refractor collimation

[hommel]

Today I manage to pull out my more than 12 years old C80 celestron refractor from the storeroom and found some spots of fungus on the objectives lens both outside/inside and in between the elements, i have intend to discard the scope so its not a concern. Views at daytime on terrestrial objects still seem quite sharp so thought i can clean up the lens instead of throwing it away.

I dismantled the lens cell to try to clean up the fungus, manage to get off most of the spots. The problem is i forget to put a mark on the orientation of the two elements and put in back after cleaning. Even without the proper marking of the position of the two elements the views is still as sharp as ever (in daytime)! Hey this scope is still usuable

So the questions is, how does a wrong orientation of elements in a refractor views look like? Even with my un professional cleaning and replacing of elements into the lens cells, the views is still sharp as before.

One thing to note is miscollimation and element orientation is two different matter, i know how a out of collimation scope looks like, but never have experience a mis match of elements in refractors.

[rcj]

Hi Jeff,

There might be several possibilities. For airspaced elements (and especially for larger refractors), a rotational mis-positioning of one of the element might lead to misalignment effects (comatic-shaped stars), but I would think it is extremely slight (though visible at high powers like 200X and beyond). It would probably indicate minute zonal differences in the lens as a result as well. Complete error in positioning of one element with another might lead to a change in longitudinal chromatic aberration, and even spherical aberration.

[hommel]

Thanks Remus, I'll take note of the comatic shaped stars, will star test this C80 some other nights just to see if the mis positioning of the elements is as crucial as perceived or have some tolerances to it.