Solar cycle 13

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The Sun with some sunspots visible.

Solar cycle 13 was the thirteenth solar cycle since 1755, when recording of solar sunspot activity began.[1][2] The solar cycle lasted 11.9 years, beginning in March 1890 and ending in February 1902. The maximum smoothed sunspot number (monthly number of sunspots averaged over a twelve-month period) observed during the solar cycle was 87.9, and the minimum was 2.7.[3] There were a total of approximately 938 days with no sunspots during this cycle.[4][5][6]

See also[edit]


  1. ^ Kane, R.P. (2002). "Some Implications Using the Group Sunspot Number Reconstruction". Solar Physics 205(2), 383-401.
  2. ^ "The Sun: Did You Say the Sun Has Spots?". Space Today Online. Retrieved 12 August 2010. 
  3. ^ SIDC Monthly Smoothed Sunspot Number. "[1]"
  4. ^ Spotless Days. "[2]"
  5. ^ What's Wrong with the Sun? (Nothing) more information: Spotless Days. "[3]"
  6. ^ Solaemon's Spotless Days Page. "[4]"