Marc Reinig wrote:

Babcock's proposed (1953) Eidophor used a mirror covered with a film of oil
scanned by an electron beam to change the local slope.

It was never implemented, however.

? Eidophors were invented by Fischer in 1939 and the first one
demonstrated in 1943. There was one still in use in a lecture theatre at
my university in the late 1970's.

There is a picture of the prototype online at:
http://www.cinephoto.co.uk/eidophor_1.htm

Regards,
Martin Brown

Marc Reinig
UCO Lick Observatory
Laboratory for Adaptive Optics

"Jan Panteltje" wrote in message
news:1111413792.625bb338adab5b3084454285a3190639@t eranews...

I have been wondering if somehow fluid lenses could be used for adaptive
optics in a telescope.
Then you could use electical voltages to change lens properties locally.
http://www.heise.de/newsticker/resul...einze%20Linsen
It is a German article, in short it describes a lens formed by a layer of
oil
on a layer of some other fluid, with an electical field applied.
These lenses are extremely small, a French company has already made a zoom
objective for a cellphone camera with this technology.
http://www.varioptic.com/en/
It uses less power then a mechanical construction.
I wonder if a big one could be made....