Mother Nature is a crafty lady. She often dazzles and terrifies us with natural events that we humans have yet to understand. One such spectacle that makes us gasp in awe is an aurora, the celestial occurrence more commonly known as the “northern lights” (aurora borealis) and “southern lights” (aurora australis). Auroras happen when the sun’s charged particles hit the Earth’s magnetic field, creating beautiful, dancing light across the sky. Yet, scientists still don’t know much about them. A new hyperspectral camera designed by space-weather researchers, however, aims to shed some more light on auroras, and may have already identified a new atmospheric phenomenon.
The NORUSCA II camera has captured the first-ever hyperspectral images of auroras. A hyperspectral camera is able to process light in different bands. Previously, cameras that were used to study auroras gather all light into one image; if researchers wanted to study the light at specific bands or a portion of the spectrum, they would have to employ filters. The NORUSCA II, using advanced optics and no moving parts to switch among all of its 41 separate optical bands within microseconds, is faster than an ordinary camera, and therefore able to filter out certain wavelengths in order to capture targeted elements within the image. The camera was tested back in January at the Kjell Henrikson Observatory in Svalbard, Norway, but the results were just published this week in the journal Optics Express.
“A standard filter wheel camera that typically uses six interference filters will not be able to spin the wheel fast enough compared to the NORUSCA II camera,” said Fred Sigernes of the University Centre in Svalbard. “This makes the new hyperspectral capability particularly useful for spectroscopy, because it can detect specific atmospheric behavior, such as the ionization of gases during auroras. This form of multispectral imaging also will enable scientists to better classify auroras from background sky emissions and study the way they cluster in the atmosphere.”
During its first use, the NORUSCA II captured images of a major solar flare. During this session, the camera was able to detect a very faint wave pattern. The new wave pattern, which researchers dubbed “airglow,” is a natural emission of light by the Earth’s atmosphere, and possibly caused by a previously unrecognized source.
“After the January CME, we think we saw an auroral-generated wave interaction with airglow,” said Sigerness. “Our new all-sky camera opens up new frontiers of discovery and will help in the detection of auroras and the understanding of how our Sun impacts the atmosphere here on Earth. Additional development and commissioning will also hopefully verify our intriguing first results.”
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