I2MOV - Radioamatore




A remarkable phenomenon that appears in the optic observation of the surface of the sun is constituted from the "sunspots." The sunspots are formations relatively dark on the solar surface with temperatures around 3000 K if compared to the surrounding zones of 6000 K.

The sunspots, whose nature is not still very clear, center of intense magnetic fields, (up to 0,4Wb/ m2) change polarity at the change of the cycle of 11 years and have polarity  opposed according to the solar hemisphere in which they are.

The sunspots vary from a minimum to a maximum, until to a new least, in around 11 years, and the available data for the old cycles are illustrated in figure 1.

Figure 1-Trend of the sunspots between 1700 and 1960

(the more ancient data are less homogeneous and less sure)

Note: On this trend for a long time term has been hypothesized the possibility of an also secular cycle superimposed to that of 11 years.

The trend of the total flux of the sun and the number of the sunspots are between them in synchronous relationship, and the atmospheric ionization varied in proportion with them; for this proportionality, at the effects of the ionization, is used the index of sunspot, rather than their number; the practical formula is:

R= K (10 g + S)


R= number index of the sunspots

g= groups of sunspot

S= single sunspot

K= empirical coefficient of proportionality.

The value R is called number of the sunspots, while would be defined like "number index of the sunspots".


Diagram performed by I2MOV from the data received by the beacon DK0WCY.

The data of the beacon was listened every day in CW on the frequency of 10144 kHz.

The monthly solar flux averages are from August 1997 to December 2019.

The level of the sunspot R = 0 corresponds about at solar flux F = 65.




Ultimo aggiornamento: 02-01-17