While searching for a method of photographing microwave interference, I
found the below.
Not off the wall, but discussed in a recent thread.
bc, stupid for not knowing the method (microwave), as is familiar w/ the
technique for developing thick cosmic-ray plates.
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Making a Mirror By Spinning a Liquid
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by Mark Dragovan and Don Alvarez
February, 1994
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WHEN A LIQUID IS SPUN IN a container, the surface of the liquid does not
remain flat but takes on a concave, parabolic shape. The parabola, of
course, is
the basis for the primary mirrors in optical telescopes because the
shape will
focus parallel light rays to a point. Investigators have exploited the
rotational
effect in fluids to make large telescope mirrors from liquid metals,
primarily
mercury. The parabolic shape remains as long as the liquid is kept
spinning.
Liquid mirrors made from mercury have been shown to have an optical
quality near their ground-glass cousins, while having the advantage of
being
lighter and less expensive [see "Liquid Mirrors," by Ermanno F. Borra, page
68].
A simpler variation of this
procedure, which can be done at
home, is to use a liquid that
hardens, so that the parabolic
surface is preserved after the
spinning has ceased. Epoxy fits
the bill. Consisting of a
mixture of
a resin and a hardener, epoxy
slowly cures to a solid with
little
change in shape. The resulting
mirror cannot compete against
aluminized glass mirrors for
image quality; it is perhaps best
suited as a collector of
light at the
infrared and microwave end of
the spectrum. We have relied on
this method to produce an
inexpensive mirror the size of a
satellite dish to be used for
observations of the cos