Large Binocular Telescope’s instruments see first light

A clever spectrograph is allowing astronomers to find further clues about the properties of distant stars and exoplanets

A relatively new high-resolution spectrograph – which can image bright objects through thin clouds and even work around the full

Moon – has received its first polarised light. The two polarimeters of the Potsdam Echelle Polarimetric and Spectroscopic Instrument (PEPSI) are able to separate starlight according to its oscillation planes. They have now been mounted in the focus points of each of the Large Binocular Telescope (LBT)'s

8.4-metre mirrors in Arizona, resulting in a powerful telescope that allows astronomers to obtain spectra in polarised light.

By pointing to the star gamma Equ, polarised light has been received.

This success means astronomers can work out the geometry and strength of magnetic fields on the surface of distant stars. They will also, according to the Leibniz Institute for Astrophysics in Potsdam Germany, be able to study the reflected light from the atmospheres of potentially habitable exoplanets. “Eventually, the PEPSI polarimeters will enable stellar magnetic field measurements with extremely high precision," says PEPSI’s project scientist Dr Ilya Ilyin.

It's a welcome addition to the LBT in Arizona, which is one of the world's most powerful optical telescopes. Allowing astronomers to probe the universe much further back than they ever could, its two mirrors act like a single telescope 22.8-metres in diameter, giving it the resolution of a far larger telescope.

This mosaic of Cassini images shows Saturn looming in the foreground “Scientists have direct measurements of the components in Saturn's upper atmosphere”

PEPSI is designed to use the two 8.4-metre apertures of the LBT to provide a high-res standby spectrograph for the LBT Observatory