SOLAR FLARE AND RADIO BLACKOUT: Sunspot AR2665 has grown into a behemoth almost as wide as the planet Jupiter: movie. Stretching more than 125,000 km from end to end and containing dozens of dark cores, the active region is an now easy target for backyard solar telescopes. Amateur astronomer Peter Desypris sends this July 9th photo from Syros island, Greece:

“This is the biggest sunspot of 2017 so far,” says Desypris. “I photographed it using an 8’inch LX200 telescope and a safe solar filter.”

On July 9th at 0318 UT the big sunspot erupted, producing an M1.3-class solar flare. Telescopes onboard NASA’s Solar Dynamics Observatory recorded the explosion’s extreme ultraviolet flash:

A pulse of UV and X-radiation from the flare ionized the top of Earth’s atmosphere. This, in turn, altered the normal propagation of shortwave radio transmissions on the dayside of our planet. A map from NOAAshows the geographical regions affected: mostly Australia and east Asia. People who might have noticed blackouts, fades, and other transmission irregularities include aviators, mariners, and ham radio operators.

Considering its extreme size, AR2665 has been relatively calm so far. Stronger flares and CMEs could be in the offing, however, as the sunspot continues to grow and turns toward Earth. Stay tuned for updates.. Free: Solar Flare Alerts