Hi Chris I think I know what you are referring to in regards to the columns of light from the streetlamps. I have just found a couple of photos which show the features quite well. Wayne Hally hit the nail right on the head when he mentioned that the cause was probably due to flat ice crytals reflecting light back down, analogous to a sun pillar. To explain things a little better I have supplied a small .gif piccy which shows the situation. The light from the streetlamp gets reflected by the flat ice crystals to the observer. The observer sees this reflected light, and appears to the observer to originate from high in the sky (the dotted lines that trace back away from the observer). Hence the observer sees the pillar. One thing that is different from the solar pillar is that these streetlamp pillars can, in priniciple, have an infinite height, and extend all the way to the zenith. This can be seen in the diagram by making the layer of ice crystals deeper, or getting closer to the light source. The solar pillar, on the other hand, is restricted to a height of about 20 degrees, but that's another topic. I've seen solar pillars before, but, to be honest, I've never given a thought to streetlamp pillars. I suppose that's due to the fact that I've never been anywhere where there has been ice crystals so low in the atmosphere. This probably explains my tact in earlier emails. Cheers -- Robert A. Goler E-mail robert@neumann.maths.monashdot edu.au http://www.maths.monashdot edu.au/~robert/ Department of Mathematics and Statistics Monash University Clayton, Vic 3168 Australia --