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.

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....