Solar cycle 20
| Solar cycle 20 | |
|---|---|
Solar magnetogram from solar cycle 20 (1974).
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| Sunspot Data | |
| Start date | October 1964 |
| End date | June 1976 |
| Duration (years) | 11.7 |
| Max count | 110.6 |
| Max count month | November 1968 |
| Min count | 12.2 |
| Spotless days | 272 |
| Cycle chronology | |
| Previous cycle | Solar cycle 19 (1954-1964) |
| Next cycle | Solar cycle 21 (1976-1986) |
Solar cycle 20 was the twentieth solar cycle since 1755, when extensive recording of solar sunspot activity began.[1][2] The solar cycle lasted 11.7 years, beginning in October 1964 and ending in June 1976. The maximum smoothed sunspot number (monthly number of sunspots averaged over a twelve-month period) observed during the solar cycle was 110.6 (November 1968), and the minimum was 12.2.[3] There were a total of 272 days with no sunspots during this cycle.[4][5][6]
Comparison with other cycles shows that geomagnetic activity during the declining phase of cycle 20 (1973–1975) was unusually high.[7]
Data from solar cycle 20 was used to build the K-1974 solar proton fluence model, used for planning space missions during solar cycle 21.[8]
See also
References
- ↑ Kane, R.P. (2002). "Some Implications Using the Group Sunspot Number Reconstruction". Solar Physics 205(2), 383-401.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ SIDC Monthly Smoothed Sunspot Number. "[1]"
- ↑ Spotless Days. "[2]"
- ↑ What's Wrong with the Sun? (Nothing) more information: Spotless Days. "[3]"
- ↑ Solaemon's Spotless Days Page. "[4]"
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
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