I think there is a beam. Your dust is just too thin. The reason why you have brighter beam above glass is that there's another beam going up, reflected from glass and wine.FarbigeWelt wrote: ↑Sat Jul 07, 2018 10:25 pm Yes, and as you can see, beam above spot of second spot light is not visible.
I tried it with laser, it gives more evident beam. But suddenly! I replaced dusty air with clear one and now there's some spectacular beam over the glass. The beam that should not be: