Ancient Viking ATMers

["Justin Kelly" <iustus@home.com>]

http://news.bbc.co.uk/hi/english/sci/tech/newsid_702000/702478.stm

The vikings are now recognized as having lenses. Once thought to be
ornaments, they have been tested and are of exellent quality. They are
eliptical, best exanple being 2 inches in diameter and one inch thick, and
made of "rock-crystal".

The article title suggests that they could have been used as telescopes, but
I am curious whether or not such an extremely convex lens really be useful
for Astronomy, or any long distance viewing at all? Perhaps they were just
used for starting fires. However, if anyone had the need for a telescope at
that time it would be the ocean navigators like the vikings.

-Justin Kelly