Sunspots: First Observations

April 5, 2009, 8:28 pm
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Oldest Written Records

The two oldest written records of a sunspot observation are found in the Book of Changes, probably the oldest extant Chinese book, compiled in China around or before 800 BC. The text reads "A dou is seen in the Sun", and "A mei is seen in the Sun." From the context, the words (i.e., chinese characters) "dou" and "mei" are taken to mean darkening or obscuration.

Astronomers at the court of the Chinese and Korean emperors made regular notes of sunspots, most less elliptical than the one cited above. It seems, however, that observations were not carried out systematically for their own sake, but instead took place whenever astrological prognostication was demanded by the emperor. The surviving sunspots records, though patchy and incomplete, covers nearly 2000 years and represents by far the most extensive pre-telescopic sunspot record. [1]

Earliest Known Drawings

The earliest known drawing of sunspots appears in "The Chronicle of John of Worcester" and predates the invention of the telescope by almost 500 years. The sunspot was recorded in medieval England in 1182, according to astronomer F. Richard Stephenson at the University of Durham. While sunspots were recorded in China more than 1000 years earlier, no Chinese drawing depicting solar spots exists until about AD 1400, and no subsequent illustration of sunspots survived until after the invention of the telescope almost 200 years later. "The Chronicle of John of Worcester" covers the historical period from earliest times to AD 1140, and contains a number of records of celestial phenomena. These include aurorae, comets and meteor showers, as well as eclipses of the Sun and Moon.

Sunspot drawing in the Chronicles of John of Worcester, twelfth century. (Reproduced from R.W. Southern, Medieval Humanism, Harper & Row 1970, [Plate VII]).

Sunspot drawing in the Chronicles of John of Worcester, twelfth century. (Reproduced from R.W. Southern, Medieval Humanism, Harper & Row 1970, Plate VII.) (Source: NASA.)

 

A large sunspot on April 7,1947 easily viewed with the naked eye near sunrise/sunset with atmospheric attenuation.

A large sunspot on April 7,1947 easily viewed with the naked eye near sunrise/sunset with atmospheric attenuation. (Source: NASA.)

One of the most interesting of these reports is a description of two sunspots seen on December 8, 1128 from Worcester, England. In the chronicle, the Latin text is accompanied by a colorful drawing that shows two large sunspots on the face of the Sun. The accompanying text translates to "...from morning to evening, appeared something like two black circles within the disk of the Sun, the one in the upper part being bigger, the other in the lower part smaller. As shown on the drawing." The fact that the Worcester monks could apparently distinguish the dark central umbrae and lighter penumbrae that surrounds the sunspots, suggests that the spots must have been truly exceptionally large.

The sunspot sighting coincided with the appearance of the aurora borealis 5 days later in Korea. On December 13, 1128 a red light in the night-time sky from Songdo (the modern city of Kaesong) was recorded in the Koryo-sa, the official Korean chronicle of the time. [2]

References

  1. ca. 800 BC: The first plausible recorded sunspot observation - Great Moments in the History of Solar Physics, University of Montreal.
  2. Technology Through Time, Issue #35: First Sunspot Drawing, "Despite a thousand years of sunspot sightings, no one thought to actually sketch what they saw until recently." NASA.

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Citation

Odenwald, Sten, Ph.D. (Contributing Author); Bernard Haisch (Topic Editor). 2009. "Sunspots: First Observations." In: Encyclopedia of the Cosmos. Eds. Bernard Haisch and Joakim F. Lindblom (Redwood City, CA: Digital Universe Foundation). [First published November 26, 2007].
<http://www.cosmosportal.org/articles/view/138729/>

 

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Citation

(2009). Sunspots: First Observations. Retrieved from http://www.cosmosportal.org/view/article/138729

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