>Mac Oglesby wrote: > >> .... a dial to indicate >> relative sunburn danger. Installed at a swimming pool or beach, this type >> of dial wouldn't even need any hour lines - regions of color would alert >> the sunbather as to when (s)he would burn most rapidly.
Ross McCluney replied: >As an optical/solar physicist, I was intrigued by this, and the possible >errors >in its use. As long as the sunbather is in a horizontal position, and not >particularly concerned about sunburn on the sides, just on the top, one could >have a vertical post gnomon with concentric circular rings around it, giving >zones of angle of incidence upon a horizontal plane. With the sun highest in (snip) Hi Ross, Thanks for your thoughtful response. Most of what you wrote hadn't occurred to me - but then I never seriously considered making such a dial myself. I guess that if a "sunburn" dial were installed in any public place, extensive disclaimers would need to accompany it. Imagine that - a "dangerous" sundial! Mac
