Liquid Mirror Telescopes Set For Magnetic Upgrade

KentuckyFC writes "Liquid mirror telescopes start life as a puddle of mercury in a bowl. Set the bowl spinning and the mercury spreads out in a thin film giving the surface an almost perfect mirror finish. But these telescopes have two important limitations. First, they can only point straight up since tilting the mirror spills the mercury. And second, they cannot be made adaptive to correct for any blurring introduced by the Earth's atmosphere. But liquid mirror telescopes look set for an upgrade thanks to the work of a group of Canadian researchers. Their technique is to change the shape of the liquid mirror using powerful electromagnets. They use a ferromagnetic fluid of iron nanoparticles in oil instead of mercury which is too dense to be easily manipulated in this way. The work is just proof of principle at this stage but the idea is to use magnets to correct for the usual range of optical aberrations that telescopes have to deal with (abstract). And also to allow a liquid telescope to be tilted by using oil that is much more viscous than mercury and correcting any periodic deformation in the fluid that tilting might cause."

Comments

All A Cover Story...

[pwnies]

This is all a secret cover up for research on how to make a robot transform into liquid metal... Sarah Conner better keep on her toes.

Smooth Magnetic Field

[MBCook]

Would it really be possible enough to make the magnetic field smooth enough so that the mirror surface was smooth and not something like the surface of a 300 sided polyhedron?

I would think it would be impractical to put enough small but powerful electromagnets behind the fluid so that you could make a smooth surface.

Or could you use something to vastly increase the surface tension thus making it easier to create a smooth surface?

Laval University

[geogob]

These works are done by a group from the Centre d'Optique et de Photonique Laser (COPL), at Laval University in Quebec City. This research center is one of the largest player in the field of optics research in North America.

I've seen this liquid mirror myself while it was in its early stages. At that time it used only mercury. It's a very impressive (and beautiful) sight. This research group, working on liquid mirrors, has been quite excited with the recent talks about lunar-based telescopes. This has always been one of the aimed application for their liquid mirror.

Too dense?

[imsabbel]

"They use a ferromagnetic fluid of iron nanoparticles in oil instead of mercury which is too dense to be easily manipulated in this way."

Well, that and the fact that a ferrofluid (== ferromagnetic or antiferromagnetic, ir depends) is a little easier to influence with magnetic fields than an weak diamagnet like mercury...