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News — Researchers at New Jersey Institute of Technology鈥檚 Center for Solar-Terrestrial Research (NJIT-CSTR) have captured the Oct. 14 solar eclipse in a way never seen before 鈥� recording the first radio images of an annular eclipse鈥檚 famous 鈥渞ing of fire鈥� effect.

The eclipse was partially visible to much of the continental U.S. for several hours that Saturday, though the full 鈥渞ing of fire鈥� effect was only visible for less than five minutes, and only for those within its聽.

However, the new observations of the radio Sun鈥檚 eclipse 鈥� much longer in duration than the partial eclipse recently experienced by millions on Earth due to the extended solar corona as seen at radio wavelengths 鈥� have yielded stunning images of the eclipse鈥檚 ring lasting for over an hour.

Researchers used the newly commissioned聽Owens Valley Radio Observatory Long Wavelength Array (OVRO-LWA)聽in the Owens Valley Radio Observatory, CA to make their breakthrough observation of radio waves emanating from the Sun's extended corona, as the moon passed between Earth and its nearest star.

鈥淭o finally see a 鈥榬ing of fire鈥� eclipse this way was spectacular 鈥� we haven't seen this quality of radio imaging of the Sun before.鈥� said Dale Gary,聽聽distinguished professor of physics and co-investigator on the OVRO-LWA project, which is funded by the National Science Foundation.

鈥淲e normally cannot see the corona from the ground except during a total eclipse, but we can now see it all the time with OVRO-LWA. This eclipse makes it that much more dramatic.鈥�

鈥淔rom our observatory site in California we were not in the belt to see the annular eclipse, yet we鈥檝e been able to 鈥榮ee鈥� it all clearly unfold in radio, which reveals a much larger solar disk than its visible counterpart thanks to its sensitivity to the extended solar corona,鈥� said Bin Chen, NJIT-CSTR associate professor of physics who led the data reduction and processing together with NJIT researchers Surajit Mondal and Sijie Yu.

鈥淪cience-wise, this is a unique opportunity to study the Sun鈥檚 extended corona with the highest resolution possible at these wavelengths, taking advantage of the moon鈥檚 limb as a moving 鈥榢nife edge鈥� to increase the effective angular resolution,鈥� said Chen.

OVRO-LWA, a multi-institutional project directed by Gregg Hallinan at California Institute of Technology, uses a set of 352 antennas to sample thousands of radio wavelengths between ~20-88 MHz.

For solar science, it offers the highest-quality images yet of the radio Sun in this wavelength regime, which is roughly two times larger than the visible solar disk.

鈥淒ocumenting this spectacular event was a great opportunity to announce the successful operation of OVRO-LWA as a new radio facility to study the Sun and many other objects including exoplanets, cosmic-rays, the early universe, and more,鈥� said Hallinan.

While the next annular solar eclipse is expected to be visible from South America in October 2024, those in the U.S. will need to wait until June 2039 to view the next 鈥榬ing of fire鈥� eclipse on home soil. However, a total eclipse visible across the central U.S. will occur sooner, next April 8.

However, the team say the recent eclipse event is an outstanding example of the first observations of the Sun with the instrument. With the new capabilities OVRO-LWA offers, exciting science is expected in the near future 鈥� particularly as solar activity of the current 11-year solar cycle peaks in 2025 during the expected "solar maximum.鈥�

鈥淲e are now working on an automated data processing pipeline that will soon produce near-real-time solar images and make them available to the public,鈥� said Chen. 鈥淭hese eclipse images serve as a proof-of-concept for this effort. The unprecedented data products coming soon will open new opportunities for discovery in solar astronomy and space weather studies.鈥�