The filter helps sharpen and define the coronal loops, making it all more easy to study
Watching a particularly beautiful movie of the sun helps show how the lines between science and art can sometimes blur. But there is more to the connection between the two disciplines: science and art techniques are often quite similar, indeed one may inform the other or be improved based on lessons from the other arena.
One such case is a technique known as a "gradient filter" – recognizable to many people as an option available on a photo-editing program. Gradients are, in fact, a mathematical description that highlights the places of greatest physical change in space.
A gradient filter, in turn, enhances places of contrast, making them all the more obviously different, a useful tool when adjusting photos. Scientists, too, use gradient filters to enhance contrast, using them to accentuate fine structures that might otherwise be lost in the background noise.
On the sun, for example, scientists wish to study a phenomenon known as coronal loops, which are giant arcs of solar material constrained to travel along that particular path by the magnetic fields in the sun's atmosphere. Observations of this phenomena can help researchers understand what's happening with the sun's complicated magnetic fields that can also power great eruptions on the sun such as the solar flares or coronal mass ejections.
Figuring out how to best process scientific imagery takes experts of all types working together to devise the new and improved methods.
For example, experts in statistics, computer recognition and image processing have all come together regularly for the last nine years at Solar Information Processing workshops to focus on sharing state-of-the-art imaging techniques that can best further scientific research. And, of course, gradients also make great art.
Through careful adjustment of gradient algorithms on this movie from NASA's Solar Dynamics Observatory, sharp loops of solar material on the sun pop out visually next to more fuzzy areas in the sun's atmosphere, providing a dazzling show.
Courtesy of Karen C. Fox
NASA Goddard Space Flight Center, Greenbelt, MD