Daniel K. Inouye Solar Telescope, the world’s largest solar telescope, located atop Haleakala Volcano on the island of Maui, recently obtained the clearest photograph of sunspots on the surface of the Sun. Thanks to a new instrument, the Visible Tunable Filter (VTF), scientists have taken the most detailed image of our star’s surface, which reveals its fiery nature with unprecedented clarity.
Key to space weather
The image, obtained in early December and published only now, shows a cluster of dark sunspots, each as large as an entire continent. These spots are areas of intense magnetic activity where solar flares and coronal mass ejections (CMEs) can occur. Such phenomena can throw huge clouds of plasma and magnetic fields into space, which, reaching the Earth, can disrupt power grids, satellites and communication systems.
“The Carrington event of 1859 showed how powerful solar storms can be – then telegraph stations burst into flames from overloading. Today, it is critical for us to understand how these phenomena affect modern technology,” notes Friedrich Woeger, a research fellow at the U.S. National Science Foundation.
How VTF operates
The VTF instrument, which means Visible Tunable Filter, is the real heart of Daniel K. Inouye Telescope. The instrument acts as a spectropolarimeter, which allows it to tune to different wavelengths of light, much like a radio receiver. This makes it possible to study the layers of the solar atmosphere by analyzing their temperature, pressure, and magnetic fields. In a matter of seconds, VTF creates hundreds of images that are combined into a three-dimensional model of the Sun’s surface.
VTF technology is based on two glass plates that create the effect of interference of light waves. This allows the instrument to filter out the right “colors” of light, allowing scientists to look deep into solar processes. “Seeing the first detailed pictures was really impressive. No other instrument can do this,” shares Stacey Sueoka, senior optical engineer at the National Solar Observatory.
Good time for discovery
Right now, our Sun is at the peak of its 11-year cycle, known as solar maximum. During this period, the star’s magnetic poles change places and more sunspots appear on its surface. This is an ideal time to test and verify the capabilities of the Inouye Solar Telescope, which is already showing impressive results.
Sunspots, according to Mark Misch, a scientist at the University of Colorado, are like “magnetic plugs” that block heat from the sun’s core. Therefore, they look darker and colder compared to other areas. However, even their temperature remains very high — 3200-4200°C.
Future of research
The development of the VTF lasted more than a decade. The instrument, built by the Institute for Solar Physics in Germany, was delivered to Maui and assembled with incredible precision. It is expected to be fully operational by 2026, opening new horizons for the study of the Sun.
This breakthrough is only part of a global effort by scientists. Missions such as the Solar Orbiter and Parker Solar Probe also help unlock the mysteries of the Sun. With technology like this, we not only have a better understanding of our star, but also learn how to protect the Earth from its turbulent nature.
New images of the Sun are not just pretty pictures, but key to predicting space weather that could affect our daily lives. And the Inouye telescope has just taken a big step toward that goal.
Earlier we reported on how the most detailed images of the Sun by the Solar Orbiter probe were published.
According to NSO
