The record-breaking Daniel K. Inouye Solar Telescope (DKIST) has captured another stunningly close look at the surface of our sun. DKIST has collected incredibly detailed images of the sun from its perch on the Haleakalā volcano in Maui since 2022, but the largest observational tool of its kind only managed its latest look thanks to a recent major milestone described as its “technical first light.” Using its newly installed spectro-polarimeter visible tuner filter (VTF), DKIST has offered a stunningly close look at the sun’s surface photosphere featuring a gigantic sunspot.
“The instrument is, so to speak, the heart of the solar telescope, which is now finally beating at its final destination,” VTF project scientist Matthias Schubert said in a statement.
VTF’s primary goal is to image the sun at the absolute highest spatial, spectral, and temporal resolutions possible. Doing so will help experts gain a better understanding of the sun’s dynamic and complex behaviors, particularly the powerful particles, solar energy, and stellar radiation it ejects across the solar system. These solar storms routinely produce colorful atmospheric auroras on Earth, but especially intense events can wreak havoc on satellites and global communications systems. Studying the sun’s photosphere and chromosphere will allow researchers to examine how plasma flows and shifting magnetic fields interact to trigger surface eruptions.
DKIST’s VTF is specifically designed to help determine attributes like magnetic field strength, temperature, pressure, and plasma flow velocity. It is a massive addition to what is already a giant observational installation. At around the size of a small garage, the 5.6 ton instrument occupies two floors at the National Solar Observatory.
The VTF was developed and constructed at Germany’s Institute for Solar Physics over the last 15 years—nearly as long as the time spent on DKIST itself. The painstaking installation process began at the beginning of 2024, and took months of work to complete before it could be utilized for the first time.
VTF’s first public image also showcases one of our star’s ever-changing sunspots, which are linked to comparatively strong magnetic fields that prevent plasma from escaping the star’s interior. To record the event, the VTF relied on sunlight with a wavelength of 588.9 nanometers, and also depicts the sunspot’s penumbra over a region measuring approximately 15,535-square-miles.
“The Inouye Solar Telescope was designed to study the underlying physics of the Sun as the driver of space weather,” said Christoph Keller, Director of the National Solar Observatory, which is responsible for operating DKIST. “In pursuing this goal, the Inouye is an ideal platform for an unprecedented and pioneering instrument like the VTF.”