Sun with sunspot group

The sunspot group formerly known as 10069 (now called 10105) has returned to the Earth-facing side of the Sun. It remains large enough to be viewed without optical aid (but a proper solar filter is a must). This picture was taken on September 12th at 3:50 p.m. EDT.

Sky & Telescope photo by Gary Seronik.

Although sunspot maximum has passed, the Sun remains active as evidenced by the strong auroral storm that took place September 7th and 8th. Now a large sunspot group that was visible in August has returned to the Earth-facing side of the Sun. During this solar rotation, the spot complex (previously designated 10069) is known as Region 10105. It has already produced several minor, but fairly bright, M-class x-ray flares since reappearing on the eastern solar limb several days ago. It's visible to the naked eye (when proper solar filters are used) and is currently near the center of the solar disk.

If you missed the aurora show earlier this month, don't despair. Although sunspot maximum has come and gone, the maximum for geomagnetic storm activity (which is most closely tied to auroral storm activity) has not yet passed. As a result, auroral storms should continue to be prevalent over the next couple of years.

Sunspot group 10105

A closer view of the sunspot group 10105 as of September 12th.

Sky & Telescope photo by Gary Seronik.

If your skies are cloudy, follow the progress of this sunspot group through the SOHO spacecraft or Big Bear Solar Observatory Web sites.

Those interested in receiving alerts about possible auroral activity can sign up for Sky & Telescope's AstroAlert e-mail news service for solar activity and auroras. More information about auroral activity and the current state of the Sun can be found on the Solar Terrestrial Dispatch Noteworthy Events Web page.


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