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On 10 September at 17:45UT, NOAA 2158 produced the 35^th X-class flare of the ongoing solar cycle. The X1.6 event was extensively covered in this news item. The images underneath show the sunspot region in white light and the corresponding magnetogram about 30 minutes prior to the flare's peak, and the flare at its maximum flux as observed in SDO/AIA 171. The flare took place along the borderline between negative (blue) and positive (red) magnetic polarity.

This movie shows the development of a magnetic delta near the initially simple sunspot group NOAA 2146, starting on 23 August. One can indeed see how a white patch (positive polarity, field lines coming out of the solar surface) gradually shaped itself south of the main spot (black, negative polarity). Then, late on 24 August, the penumbra of both spots merged and gave NOAA 2146 a delta configuration.

Remember NOAA 2126? This relatively small sunspot group was visible from about 23 July till 3 August. It was flanked to the north and south by resp. NOAA 2129 and NOAA 2123, which were smaller and simpler sunspot groups. During its transit, NOAA 2126 produced only a few small C-class flares.

The Sun had its own mountain stage this month, with soaring sunspot numbers during the first week, then a fast decline until sea-level values (that is: zero sunspots) were reached on the 17th, followed by a gradual recovery to more moderate sunspot numbers. This can be seen in the evolution of the estimated daily sunspot number as compiled by SILSO, and shown in graph underneath.

Late on 26 June, an eruption took place in an active region just behind the Sun's east limb. The event led to some spectacular images of the associated coronal mass ejection (CME) and post-flare coronal loops.

The eruption started around 21:00UT, and the expanding CME can be seen in extreme ultraviolet (EUV) in SDO, STEREO-B and PROBA2 imagery, as indicated with the dashed orange lines in the images underneath.