World Data Center for the production, preservation and dissemination of the international sunspot number


Sunspot number series: latest update

Daily estimated sunspot number
20 February : 32
21 February : 26
22 February : 25
23 February : 21
24 February : 21

New 'Spotless days' page

Regular solar observers have noticed that since mid-2016, the Sun has occasionally been devoid of sunspots. As the current solar cycle 24 will gradually give way to the new solar cycle 25, several consecutive days and even weeks without sunspots will become the norm. In order to have an idea on the number of spotless days, and how these numbers compare to past solar cycles, SILSO has created a “Spotless Days page”. This page contains graphs and tables on the accumulated number of spotless days, stretches of spotless days, and comparisons to other solar cycles – all supplemented with a word of explanation.
Will the upcoming solar cycle minimum show as many spotless days as the previous one, or will solar cycle 25 take off much faster than expected? This “Spotless Days page” will provide you with a front-row seat on the current status of the solar cycle minimum and the number of spotless days. Enjoy!
LINK : Spotless days
Tue, 03 Jan 2017
Latest USET observations (ROB, Brussels) 24/02/2017

Latest USET drawing

Latest USET image
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