Quote:
Originally Posted by Startrek
Jason
but the images were showing stars with one end blurred and irregular shaped.
Yes the secondary was not centred down the focuser. I never mentioned it was way out.
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Martin, both statements are inconsistent. I am not questioning your observation but rather the conclusion. There are three collimation alignments:
1- Optimizing field illumination:
-- Using a sight-tube/cheshire tool, this alignment is done by ensuring the secondary mirror is centered/rounded under the focuser.
-- This alignment can't be done using a regular laser collimator unless a special holographic attachment is used.
2- Eliminating focal plane tilt:
-- Using a sight-tube/cheshire tool, this alignment is done by adjusting the secondary mirror to stack the cross-hairs with the primary mirror center spot
-- Using a laser collimator tool, this alignment is done by adjusting the secondary mirror to redirect the laser beam to the primary mirror center spot
3- Eliminating coma:
-- Using a sight-tube/cheshire tool, this alignment is done by adjusting the primary mirror to stack the tool's pupil reflection with the primary mirror center spot
-- Using a laser collimator tool, this alignment is done by adjusting the primary mirror to redirect the returned laser beam back to its source.
The observed issue you have reported is more consistent with misalignments that relate to the 2nd/3rd descriptions above which are within the laser collimator capabilities. A misalignment that relates to the 1st description is manifested as an uneven/off-center illumination but should not impact diffraction, sharpness and/or shape of stars -- unless it is way off.
It is possible that there could have been other factors that led to your observation.
Jason