Diffuse halos around bright stars with narrowband filters
Posted 27 January 2021 - 09:40 AM
I use UltraBlock and Lumicon OIII filters with XT8 dobsonian (visual only). The filters work great on nebulas. But I noticed diffuse halos around bright stars (e.g. Rigel) with them. Is that normal? Would flocking the tube provide any help?
Posted 27 January 2021 - 11:37 AM
This could be caused by slight roughness in the filter coatings / layers. It is like looking through a slight fog. I have not noticed it on Lumicon filters, but your eyesight might be better than mine.
Flocking will not help it.
Posted 27 January 2021 - 11:42 AM
most likely a little bit of moisture or dust in your air.
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