This crisp view of a sunspot, captured by New Jersey Institute of Technology's New Solar Telescope and released last week, may be the most detailed picture of its kind yet shot in visible light, astronomers say.
The 5.25-foot (1.6-meter) telescope, which became operational last year, sits at the school's Big Bear Solar Observatory in the San Bernardino Mountains of California. The device uses a special deformable mirror—part of what's called an adaptive optics system—to compensate for atmospheric distortions and produce ground-based images with about the same clarity as shots from orbiting observatories, experts say.
High-resolution sunspot pictures in many types of light help scientists better understand solar storms and space weather, which can disrupt navigation and communication systems on Earth and expose people in spacecraft or airplanes to potentially harmful radiation. (Read "Magnetic-Shield Cracks Found; Big Solar Storms Expected.")
A different view of the sunspot seen in the previous picture reveals dark jets of energy flowing from the spot's bright edges.
Sunspots are regions of intense magnetic activity on the sun's surface. This activity cools a region of surface material as compared with its surroundings, which is why the spots appear dark in visible light. (See "Sunspot Delay Due to Sluggish Solar 'Jet Stream'?")
The angle of this shot, taken July 1, shows magnetic activity in the sun's atmosphere 1,000 miles (1,609 kilometers) higher than in the previous frame, captured July 2. (See more sun pictures.)
Image courtesy BBSO/NJIT
The sun takes on a different appearance when viewed in a single wavelength of light, as captured by instruments on the space-based Solar Dynamics Observatory July 1.
A wavelength is the distance a particular wave travels before it repeats its shape, such as the space from one crest to the next. Red light, for instance, can have wavelengths from 620 to 750 nanometers.
Because different chemicals absorb and emit light in specific wavelengths, viewing the sun in individual wavelengths can reveal a variety of phenomena as they take place in the solar orb's many layers. (Related: "NASA Solar Observatory's First Shots.")
"This 304-nanometer image is of the helium line, a layer of the atmosphere far above where sunspots form," NASA's Pesnell said. "It's kind of like looking at the clouds in Earth's atmosphere rather than at the surface of the Earth itself."
Image courtesy SDO/NASA
The atmospheric distortion that makes stars twinkle at night plays havoc with ground-based observations of the sun, according to Pesnell.
"It can make it appear like you're looking at it through rippling water," he said.
The New Solar Telescope (seen above in an undated photo) corrects for this effect using a computerized system that measures atmospheric distortion and deforms the telescope's mirrors to compensate, bringing the sun into strikingly sharp focus, experts say.
By summer 2011 the solar telescope will be using a larger, more powerful mirror for this process, which should further upgrade its performance.