On 2003-11-27, Timothy O'Connor wrote:

This is a really stupid question (that someone asked me the other day, and I
didnt have any reasonable answer), but why is it not possible to simply mold
a mirror to shape, rather than grind it? I would have thought that it would
be possible get it done with a great deal of acuracy these days. (obviously
not, but Im not sure why)

Some mirrors for very large telescopes are molded to reduce the amount
of work needed to grind and polish. It isn't possible to mold a mirror
accurately enough to use as it comes from the mold.

--
When the fog came in on little cat feet last night, it left these little
muddy paw prints on the hood of my car.