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Last Post 3/22/2012 12:25 AM by  Emilia Kilpua
sun spots
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3/21/2012 12:43 PM
    How many sunspots have been recorded in all?
    Tags: sunspots, history, Tracking

    Emilia Kilpua

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    3/22/2012 12:25 AM

    That is a really tough question!

    In the mid nineteenth century Swiss astronomer Rudolf Wolf started to record the number of sunspots in a systematic way. His sunspot number, called Wolf number of International sunspot number, has been tabulated now for over 150 years. You can find his recording e.g. from (There a graphs, but you may also download the actual data). However, the Wolf sunspot number does not directly give the actual number of individual spots detected at the Sun. It is the relative sunspot number that depends on the number of individual spots and the number of sunspot groups. You can read more on the counting of sunspot from:
    During solar minimum the sunspot number can be zero and according to the largest recorded sunspot number of 355 was recorded in December 24 and 25, 1954. Using the data from SIDC I summed up their daily sunspot numbers from 1818 and the result was 3624090. But remeber that this does not give the number of individual spot. For example, if you look picture of the Sun from you can see today five sunspot groups, and the total sunspot number is 62.


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