World’s biggest solar scope sees sunspots as never before

A brand-new instrument has captured a cluster of sunspots — dark surface spots caused by strong magnetic fields — on our glorious Sun in an unprecedented amount of detail. This image was taken during the first-light observation of the new Visible Tunable Filter (VTF), which was recently installed on the U.S. National Science Foundation’s Daniel K. Inouye Solar Telescope (DKIST), the world’s most powerful solar telescope, near the summit of Maui’s Haleakalā in Hawaii.

The VTF is designed to isolate specific wavelengths of light from the Sun and scan through them quickly, allowing scientists to take hundreds of narrowband images in just seconds. DKIST’s 4-meter mirror — the largest ever in a solar telescope — means its images are also the highest resolution solar images ever acquired.

This intricate image of the Sun was taken at a wavelength of 588.9 nanometers — commonly known as one of the sodium-D lines. These spectral lines are created when sodium atoms in the Sun’s atmosphere absorb specific wavelengths of light, and they are useful to study Doppler shifts due to the surface’s motion, solar flares, and much more. Each pixel in the original photograph corresponds to 6.2 miles (10 kilometers) of the solar surface. An image of the continental United States is superimposed in the bottom right corner for scale. 

The VTF — which has been in the works for over a decade — is still in its commissioning phase, and won’t be fully operational until 2026. But scientists say its initial images provide an exciting glimpse into how compelling future results will be.

“The significance of the technological achievement is such that one could easily argue the VTF is the Inouye Solar Telescope’s heart, and it’s finally at its forever place,” said KIS VTF Project Scientist Dr. Matthias Schubert in a press release.