Refractor Collimation

Too many clouds and too much time on my hands. When collimating a refractor with a
Cheshire (or a TAK Collimator), will I get a different set of doughnuts to align in
an airspaced triplet compared to an oil spaced triplet objective? Seems like the
center element in the oil trilet will not reflect back? Should both look the same
in collimation with concentric lined-up doughnuts? I've never collimated an oil
spaced scope.
Thanks,
Wes

Wes Bolin said:

Too many clouds and too much time on my hands. When collimating a refractor with a
Cheshire (or a TAK Collimator), will I get a different set of doughnuts to align in
an airspaced triplet compared to an oil spaced triplet objective? Seems like the
center element in the oil trilet will not reflect back? Should both look the same
in collimation with concentric lined-up doughnuts? I've never collimated an oil
spaced scope.
Thanks,
Wes

Wes,

You only get two reflections from an oiled triplet, and it is just a matter of making them appear concentric.

Clear skies, Alan