and the Solar Max

The Butterfly Diagram


Detailed observations of sunspots have been obtained by the Royal Greenwich Observatory since 1874. These observations include information on the sizes and positions of sunspots as well as their numbers. These data show that sunspots do not appear at random over the surface of the sun but are concentrated in two latitude bands on either side of the equator. A butterfly diagram (appropriately named because of its appearance) highlighting the positions of the spots for each rotation of the sun since May 1874 shows that these bands first form at the sun's mid-latitudes, widen, and then move toward the equator as each cycle progresses. By the time the sunspots reach the equator, the cycle is at a minimum, and new spots are beginning to form again at the mid-latitudes.


Sunspots and the Solar Max
What exactly is a sunspot?
The Butterfly Diagram
The Solar Wind

Butterfly Diagram Butterfly Diagram

above: Butterfly Diagram (Image courtesy NASA Marshall Space Flight Center)

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