Measuring Solar Activity

  • Lee Macdonald
Part of the Patrick Moore’s practical astronomy series book series (PATRICKMOORE)


The easiest and most useful type of solar observations an amateur astronomer can make is to measure the level of activity seen on the Sun. This is best done by counting the number of sunspots and/or sunspot groups visible on the Sun’s disc each day. Other methods of measuring solar activity are used by professional observatories, but counting is the only one that is practical for the amateur. Sunspot counts are very useful in monitoring the Sun’s behaviour and one type of sunspot count, known as the Relative Sunspot Number, is an internationally recognised measurement of sunspot activity.


Solar Activity Sunspot Number Sunspot Group Sunspot Activity Relative Sunspot Number 
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Copyright information

© Springer-Verlag London 2003

Authors and Affiliations

  • Lee Macdonald

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