Here a practical link for optical calculations like Brewster angle
https://refractiveindex.info/?shelf=main&book=Ni&page=Johnson J.W.
Thanks for the feedback. I had not heard of Brewster's angle. I will need time to consider these suggestions. Harry On Fri, Aug 11, 2023 at 3:11 PM MSF <foster...@protonmail.com> wrote: We call them "colors" down here south of the border, Harry. But to your question, yes I have experienced the same phenomenon. Keep in mind that peripheral vision is more light sensitive than foveal vision. I can think of two possibilities to explain the phenomenon. Light from the clear sky is partially polarized along a north to south axis. So if you are walking in a mostly north or south direction you would see these colors to your left or right as the angle to the area you are observing is around Brewster's angle. They would be secondary colors. Alternatively, it might just be a very thin oil slick formed from the asphalt and you need the more sensitive peripheral vision to perceive it. More than you wanted to know, probably. ------- Original Message ------- On Wednesday, August 9th, 2023 at 7:36 PM, H L V <hveeder...@gmail.com> wrote:This summer I have been walking to work in the morning during twilight just before the sun rises. As I walk across asphalt paved streets which are old and cracking, sometimes I see very faint bands of colour in my peripheral vision when I am looking at the pavement. When it happens I am walking roughly southward ( at 46 degrees north latitude) and the bands seem to appear on the left side of my peripheral vision. The colours remind more of those found in the Goethe spectrum rather than the rainbow spectrum. I wondered if it might be an effect of LED street lighting reflecting off the pavement but sometimes it seems to arise far from any LED street lights. Has anyone else experienced this? Harry
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