SFI = 165 A index = 18 K index = 2 SSN = 117 The SunSpot Number (SSN) is a commonly used index of solar activity. The daily sunspot. number was first introduced in 1848 by the Swiss astronomer, Johann Rudolph Read moreā¦
SFI = 165 A index = 18 K index = 2 SSN = 117 The SunSpot Number (SSN) is a commonly used index of solar activity. The daily sunspot. number was first introduced in 1848 by the Swiss astronomer, Johann Rudolph Read moreā¦