dew heaters may soon be obsolete..

[phobos (John)]

researchers at MIT have developed a coating to prevent fog...

http://web.mit.edu/newsoffice/2005/fog.html

[h0ughy (David)]

I hope it becomes commercial very quickly, won't stop frost though!

[bird (Anthony Wesley)]

I think this coating would be a very bad thing for use on your secondary (or primary). The water still forms on the surface, but it's in a sheet and not as separate droplets, so you would get a large image degradation from the water layer without the dimming that usually happens with normal fog to let you know that it's there...

Bird