Italian scientists prepare new solar instrument for crucial eclipse test

Sheltered from the blazing summer sun, a group of scientists in the northern Italian city of Padua spent weeks in a laboratory finalising an instrument they say could transform the study of the solar corona, the outer layer of the sun's atmosphere.

As a total solar eclipse sweeps across Europe on August 12, the Circular Slit Spectrometer (CISS) will undergo a decisive test at Spain's Javalambre Astrophysical Observatory, where researchers hope to prove it can break down the Sun's light into its constituent wavelengths much faster than existing instruments.

The eclipse creates conditions where the corona becomes more visible, facilitating studies of the area around the sun whose behaviour has huge potential to impact communications networks and power grids on Earth.

Unlike conventional linear spectrometers, the new prototype "has a circular slit and can capture the spectrum of the entire corona at a certain distance from the centre of the Sun in a single photograph," said Principal Investigator Federico Landini of the Astrophysical Observatory of Turin.

NEW OPTICAL PRINCIPLE

The approach is designed to overcome a key limitation of earlier instruments, which could take hours to scan the corona line by line while the region changes on timescales of minutes.

If researchers can demonstrate that the new optical principle works, the next step could be to apply it to a future space mission to observe the Sun's outer atmosphere.

The last major ultraviolet spectrometer, UVCS, operated aboard the European Space Agency and NASA's SOHO spacecraft from 1996 to 2013, but required many hours to map the entire corona.

First, however, they must be ready for the brief window of totality, when the Moon blocks the sun, allowing scientists to observe the corona and putting 2-1/2 years of work to the test.

"There is neither space nor time for the unexpected," said Senior Researcher Paola Zuppella of the Institute for Photonics and Nanotechnologies in Padua. Team coordination, she added, would be just as important as favourable weather conditions.

To reach Spain, the team left by road on Friday rather than flying, transporting the instrument in a van so it would not have to be dismantled and reassembled on arrival. They also hoped to avoid any disruption to their journey.

"Given the situation with flights, which may well be cancelled at the last minute, it's best to make sure we actually get there," Landini said.

-Writing by Matteo Negri; Editing by David Holmes/Reuters