Free Astronomy Magazine July-August 2014

INSTRUMENTS A bove: one of the first lights of SPHERE show- ing the dust ring around the star HR 4796A, in the constellation Cen- taurus. The light from the star has been almost com- pletely suppress- ed. Left, Titan in visible light, and (to the right) in polarized light, which highlights the haze at the edge [ESO/J.-L. Beu- zit et al./SPHERE Consortium] times per second, with nanometric precision. This based on the alterations found in the image of an artificial star, created in the upper atmosphere by the laser beams of the telescope to which SPHERE is combined – namely, unit 3 of the VLT (Melipal). A second strong point of SPHERE is a high-precision coronograph, used to block out nearly all the light of the stars, allowing to view their planets. But the real differ- ence, compared to previous genera- tions of similar in- struments, is in the differential imag- ing devices, which use several col- ours of the visible and near-infrared spectrum and the