World’s most powerful solar telescope reaches historic milestone with first data online

On Wednesday, February 23, 2022, the U.S. National Science Foundation’s (NSF’s) Daniel K. Inouye Solar Telescope (Inouye Solar Telescope) commenced its first science observations, signaling the start of its year-long operations commissioning phase and a new era of solar science. Over 25 years in the making, the world’s most powerful solar telescope is now poised to revolutionize our understanding of the Sun and its impacts on Earth. 

“We are proud to bring the world’s largest and most powerful solar telescope online,” said Dr. Sethuraman Panchanathan, NSF Director. “The NSF’s Daniel K. Inouye Solar Telescope is a modern technological marvel, named in honor of late Senator Inouye, an American hero, and leader dedicated to scientific research and discovery.”

Hailed as the “crowning achievement” for ground-based solar astronomy, the Inouye Solar Telescope utilizes the next generation of solar observing instruments capable of capturing images of the Sun in unprecedented detail. The facility operates at 10,000 ft above sea level near the summit of Haleakalā on Maui, Hawai‘i, where unique environmental conditions enable observations of the elusive solar corona. The telescope’s operational phase is a long-awaited accomplishment, marking the end of a construction phase bookended by groundbreaking in 2012 and an 18-month delay caused by the COVID-19 global pandemic.

“The Inouye Solar Telescope team remained committed to developing an innovative solar telescope that pushed the frontiers of new technology. From design through construction, they overcame many challenges to realize a world-class facility poised to deliver on its transformational potential for all of humankind,” said Dr. David Boboltz, Program Director in NSF's Division of Astronomical Sciences.

The Inouye Solar Telescope will take high-resolution images and make measurements of the magnetic fields of solar phenomena including sunspots, solar flares, and coronal mass ejections. Solar activity drives space weather events that can impact Earth by disrupting power grids, communication networks, and other technology we depend on. The Inouye Solar Telescope, in concert with other advanced observatories, will provide greater insight into space weather behavior to aid in developing the means of predicting such events.

“Taking the first science observations with the Inouye Solar Telescope marks an exciting moment for the solar science community,” commented Dr. Thomas Rimmele, NSO Associate Director and lead of Inouye Solar Telescope, “There is no other facility like the Inouye Solar Telescope. It is now the cornerstone of our mission to advance our knowledge of the Sun by providing forefront observational opportunities to the research community. It is a game-changer.”

In 2020, the Inouye Solar Telescope’s “First Light” campaign previewed the powerful optical systems by producing the highest resolution image of the solar surface ever taken, followed six months later by the clearest image ever taken of a sunspot. The facility combines numerous state-of-the-art systems including a 4-meter primary mirror, adaptive optics to correct for the effects of the atmosphere, active cooling of all telescope optics, and advanced optical and infrared instrumentations. The combination of instruments is capable of many feats, ranging from capturing images of our Sun's features three times smaller than previously recorded to facilitating regular measurements of the solar corona’s magnetic fields for the very first time. 

This landmark event has been eagerly anticipated by the global solar community. Operations begin with a 12-month commissioning phase as the telescope is gradually brought online. This is a period of “shared risk” where scientists understand that there may be issues to be solved while they exercise the many observing modes of this complex facility, its instruments, and data systems. 

The Inouye Solar Telescope’s resident scientists and operators will execute selected scientific observations, chosen via a peer-reviewed proposal process based on the experiment’s objectives, viewing conditions, and available solar features. The Visible Broadband Imager (developed by the NSO), the Visible Spectro-polarimeter (developed by the High Altitude Observatory), and the Cryogenic Near-Infrared Spectro-polarimeter (developed by the University of Hawai‘i) will be available to the initial phase of scientific proposals. A second infrared spectro-polarimeter, also developed by the University of Hawai‘i, will be made available during the second proposal call expected to be announced early next year. 

The selected science proposal titled, “Electric Field Associated with Magnetic Reconnection Driving a Jet in the Chromosphere” was led by Dr. Tetsu Anan, Principal Investigator with the National Solar Observatory.

The experiment is designed to verify a process known as “magnetic reconnection” by measuring electric fields that are believed to occur during this process. Magnetic reconnection is the mechanism by which solar magnetic fields are suddenly and energetically reconfigured, resulting in jets of plasma ejected from the solar atmosphere. This process has long been theorized but has yet to be proven. Observations from the Inouye Solar Telescope’s unique suite of instruments are allowing scientists to observe this elusive but vital phenomenon for the very first time.

"It is an honor to have been selected as the first science experiment executed at the Inouye Solar Telescope," said Anan, "This a moment we've all looked forward to - a historic welcoming to the new age of solar observations. I’d like to thank the co-investigators and everyone involved with the Inouye Solar Telescope for this monumental milestone.” 

Dr. Jiong Qiu, Montana State University, was one of several co-investigators involved in the experiment. “Magnetic reconnection is the keyword in many energy release events in the Sun's atmosphere,” said Qiu, “For many years, solar physicists could only infer or estimate an average reconnection electric field based on many assumptions. I am hopeful that being able to directly measure this crucial physical parameter with the enabling technology by the Inouye Solar Telescope will bring breakthroughs in solar physics and revolutionize our understanding of magnetic reconnection.”

NSF’s Daniel K. Inouye Solar Telescope Data Center in Boulder, CO is an integral part of the telescope’s operations. The Data Center will receive the data from the telescope, curate and store the data, calibrate it, and distribute it to scientists and the public. Once data from a proposal has been calibrated, the principal investigators & co-investigators will have exclusive access to the data for six months, after which it will be made publicly available.