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- Sunspots usually appear in groups that are dominated by a leader spot (western side of the group) and one or more trailer spots (eastern side) with the leader spot often being the largest in the group.
- Magnetic fields in sunspots reach 3000 gauss.
- Leader and trailer spots have opposite polarity.
- During each 11 year solar cycle, leader spots in one hemisphere have a given polarity and those in the other hemisphere, the opposite polarity. The polarities in each hemisphere reverse during the next solar cycle. So the actual solar activity cycle is ~23 years long.
- During Solar Cycle 21 which reached its peak in 1979-80, the northern hemisphere leader spots had positive polarity (magnetic field pointing outward from the surface --> north polarity).
- The first sunspots of a new cycle appear at off-equatorial latitudes.
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