Very interesting proposition G Day It is hard to imagine that any material could have a negative index I would love to read more do you have a link to anything showing the materials that are able to produce negative refraction?. I assume this would mean in the practical sense that one would use a concave lens as an objective in place of the convex objective lens in a refractor
. If thats the case better performance would come from less "glass" for the light to travel thru I suppose??
alex
.