Imma Perfetto
Cosmos science journalist
The world’s biggest solar telescope has delivered its first images with a new instrument, showing the Sun’s explosive surface in exceptional detail.
The Daniel K Inouye Solar Telescope in Hawaii – with a primary mirror diameter of 4m – took the images with its Visible Tunable Filtergraph (VTF) spectro-polarimeter.
The telescope has been taking scientific observations since 2022, but its newest upgrade holds the key to better understanding the processes that trigger solar eruptions.
“The Inouye Solar Telescope was designed to study the underlying physics of the Sun as the driver of space weather,” says Dr Christoph Keller, director of the National Solar Observatory which operates the telescope atop the Haleakala Volcano on the Hawaiian island of Maui.
“In pursuing this goal, the Inouye is an ideal platform for an unprecedented and pioneering instrument like the VTF.”
The VTF allows the telescope to peer more closely than ever at the visible surface of the Sun, the photosphere, and the adjacent layer of the solar atmosphere, the chromosphere, where powerful solar eruptions originate.
These include giant bursts of radiation called solar flares, or bursts of particles and magnetic field called coronal mass ejections.
When Earth is in the line of fire of these events, solar bombardment can trigger spectacular auroras and disrupt satellites and other infrastructure, including power networks and high-frequency radio communications.
The VFT determines important solar properties – such as plasma flow velocity, magnetic field strength, pressure, and temperature – to understand the complex interaction between plasma flows and changing magnetic fields.
It does so at high resolution, about 10km per pixel, and with hundreds of images taken per second, allowing astronomers to explore the evolution of the sun’s surface over time.
“VTF enables images of unprecedented quality and thus heralds a new era in ground-based solar observation,” says Dr Sami Solanki, director at the Max Planck Institute for Solar System Research in Germany.
