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."