Solar cycle 11

{{Infobox Solar cycles

|cycle_num=11

|image=PSM V05 D555 The photosphere and sun spots.jpg

|caption=Sunspots observed during solar cycle 11 (1873)

|start_date=March 1867

|end_date=December 1878

|duration=11.8

|max_count=234.0

|max_count_date=August 1870

|min_count=9.9

|spotless_count=1028

|prev_name=Solar cycle 10

|next_name=Solar cycle 12

|prev_dates=1855–1867

|next_dates=1878–1890}}

File:Oslo-prominences.pngs observed by Carl Frederik Fearnley during solar cycle 11 (1872–1873).]]

Solar cycle 11 was the eleventh solar cycle since 1755, when extensive recording of solar sunspot activity began.{{citation|doi=10.1023/A:1014296529097|year=2002|last1=Kane|first1=R.P.|title=Some Implications Using the Group Sunspot Number Reconstruction|journal=Solar Physics|volume=205|issue=2|pages=383–401|bibcode=2002SoPh..205..383K}}{{cite web | title=The Sun: Did You Say the Sun Has Spots? | url=http://www.spacetoday.org/SolSys/Sun/Sunspots.html | publisher=Space Today Online | accessdate=12 August 2010}} The solar cycle lasted 11.8 years, beginning in March 1867 and ending in December 1878. The maximum smoothed sunspot number observed during the solar cycle was 234.0 (August 1870), and the starting minimum was 9.9.SIDC Monthly Smoothed Sunspot Number. "[http://sidc.oma.be/sunspot-data/]" During the minimum transit from solar cycle 11 to 12, there were a total of 1028 days with no sunspots (the highest recorded of any cycle transit to date).Spotless Days. "[http://spaceweather.com/glossary/spotlessdays.htm?PHPSESSID=dli444kmrjgre0rjq6l86fv144]"{{cite web |url=https://science.nasa.gov/headlines/y2008/11jul_solarcycleupdate.htm|archive-url=https://web.archive.org/web/20080714032353/https://science.nasa.gov/headlines/y2008/11jul_solarcycleupdate.htm|url-status=dead|archive-date=14 July 2008|title=What's Wrong with the Sun? (Nothing)|date=11 July 2008|author=Dr. Tony Phillips|publisher=NASA}}Solaemon's Spotless Days Page. "[http://users.telenet.be/j.janssens/Spotless/Spotless.html]"

Strong auroral displays were observed in October 1870, February 1872, and August 1872.{{Cite web|url=http://www.solarstorms.org/SRefStorms.html|title=Space Weather Newspaper Archives|first=Solar|last=Storms|date=28 July 2017|website=www.solarstorms.org}}