The sun might be responsible for light and life on Earth, but it can also be terrifying. The first image from the brand new Visible Tunable Filter (VTF) instrument at the Daniel K. Inouye Solar Telescope shows the sun’s surface in detail, highlight a patch of sunspots that looks like something out of a horror movie.
The image is the “first light” of the new instrument, meaning it is the first full image captured since the VTF was installed. It is a type of instrument called an imaging spectro-polarimeter, which takes two dimensional images of the sun in particular wavelengths. Whilst most cameras, and our eyes, can detect a range of wavelengths, this instrument takes images of just one wavelength at a time, adjusting through different wavelengths by tiny differences of a billionth of a meter. In effect, it’s like taking a series of different photographs, each one filtered for a different color.
The VTF can take hundreds of images in a few seconds, then these different wavelength readings can be combined into one set of data to build out a 3D picture of an object — in this case, the surface of the sun. The image is just a part of the testing of the instrument, which is expected to become fully operational next year.
“Seeing those first spectral scans was a surreal moment. This is something no other instrument in the telescope can achieve in the same way,” said Stacey Sueoka of the National Solar Observatory, which operates the telescope. “It marked the culmination of months of optical alignment, testing, and cross-continental teamwork. Even with just one etalon in place, we’re already seeing the instrument’s potential. This is only the beginning, and I’m excited to see what’s possible as we complete the system, integrate the second etalon, and move toward science verification and commissioning.”
An annotated version of the image includes a representation of the US for scale, showing just how vast these sunspots can be.
These sunspots are related to the sun’s activity and can often lead to solar flares or coronal mass ejections, which are such powerful outflows of plasma that they can even affect us here on Earth. The plasma travels out from the sun and toward Earth, where it interacts with the atmosphere in a phenomenon called space weather. This can create beautiful auroras, but it can also disrupt communications and cause other problems.
Tools like the instruments on the Inouye telescope can help researchers understand more about the sun’s activity and how that drives space weather, so it can be better predicted in future.
