Thread: Solar Halo
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Old 2020-10-08, 19:04   #6
xilman's Avatar
May 2003
Down not across

1049610 Posts

Originally Posted by bsquared View Post
I would like to know more about this.
Back when I was a grad student, about 1980 or so, and living in Oxford we had several cm of snowfall. Subsequent days had a maximum temperature just barely above freezing with most of the time spent significantly below zero. Consequently the snow almost melted and then re-froze to form coarse crystals which acted as crude corner-cube reflectors.

One night I was walking towards St Catz through the wooded area nearby. Street lights and the like produced very obvious halos of light when viewed at 180 degrees away from them. At a few places in my walk there were no sources of artificial light, only stars and Jupiter. I could still see a faint but clear halo with a darker circular centre which was antipodal to Jupiter. If I moved to put Jupiter behind a tree the halo disappeared.
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