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NOAA 2599 transited the solar disk from 3 till 15 October. It reached its largest size around 5 October, when its area was equivalent to nearly 3 times the total surface area of the Earth. During its transit, it significantly changed from outlook, becoming smaller and less complex. Solar observers watching the Sun only at the beginning and the end of the period might even have had a hard time to conclude this was the same sunspot.

A filament eruption took place early on 1 October (see movie). This filament had a respectable length of about 40 degrees, i.e. more than 10% of the solar circumference or well over the average Earth-Moon distance. The feature was already visible during the previous solar rotation early September, when it transited the solar disk uneventfully (see this news item).

For the second consecutive week, no C-class flares were observed from Earth. In fact, not a single C-class flare has been recorded so far this September month, with the last C-class event dating back already from late on 31 August. Records will not be broken soon though, as the longest period without a C-class flare was set during the past solar cycle minimum from 3 April till 3 November 2008 (213 days!).

The deadline Sept 12th for nomination for one of the prestigious medals in space weather, linked with the European Space Weather Week is approaching.

On 1 October 2014, communications with the STEREO-B spacecraft were interrupted during a planned test in anticipation of its solar conjunction at the Sun's farside (see image underneath for positions relative to Earth). Despite intense recovery efforts in the subsequent months, contact could not be re-established and the spacecraft seemed to be lost. More background information can be found in the news items of 4 June 2014 and 29 July 2015.