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Old 29-10-2020, 05:45 PM
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Merlin66 (Ken)
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Join Date: Oct 2005
Location: Junortoun Vic
Posts: 8,927
Marc,
When using the H alpha etalons, there’s no “filter” involved.
Any dust donuts are usually are associated with the cover glass on the camera.
Preparing “plastic bag” flats are far more successful when you image surface images, full disk are problematic.
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