Solar observation

Solar observation is the scientific endeavor of studying the Sun and its behavior and relation to the Earth and the remainder of the Solar System. Deliberate solar observation began thousands of years ago. That initial era of direct observation gave way to telescopes in the 1600s followed by satellites in the twentieth century.at the fourth hour of the day ... darkness covered the earth and all the brightest stars shone forth. And it was possible to see the disk of the Sun, dull and unlit, and a dim and feeble glow like a narrow band shining in a circle around the edge of the disk.In the third year of Lothar, emperor of the Romans, in the twenty-eighth year of King Henry of the English...on Saturday, 8 December, there appeared from the morning right up to the evening two black spheres against the sun.In the evening there as an eclipse of the sun. It was getting very gloomy and stars were seen ... The sun became similar in appearance to the moon and from its horns came out somewhat like live embers. Solar observation is the scientific endeavor of studying the Sun and its behavior and relation to the Earth and the remainder of the Solar System. Deliberate solar observation began thousands of years ago. That initial era of direct observation gave way to telescopes in the 1600s followed by satellites in the twentieth century. Stratigraphic data suggest that solar cycles have occurred for hundreds of millions of years, if not longer; measuring varves in precambrian sedimentary rock has revealed repeating peaks in layer thickness corresponding to the cycle. It is possible that the early atmosphere on Earth was more sensitive to solar irradiation than today, so that greater glacial melting (and thicker sediment deposits) could have occurred during years with greater sunspot activity.This would presume annual layering; however, alternative explanations (diurnal) have also been proposed. Analysis of tree rings revealed a detailed picture of past solar cycles: Dendrochronologically dated radiocarbon concentrations have allowed for a reconstruction of sunspot activity covering 11,400 years. Solar activity and related events have been regularly recorded since the time of the Babylonians. In the 8th century BC, they described solar eclipses and possibly predicted them from numerological rules. The earliest extant report of sunspots dates back to the Chinese Book of Changes, c. 800 BC. The phrases used in the book translate to 'A dou is seen in the Sun' and 'A mei is seen in the Sun', where dou and mei would be darkening or obscuration (based on the context). Observations were regularly noted by Chinese and Korean astronomers at the behest of the emperors, rather than independently. The first clear mention of a sunspot in Western literature, around 300 BC, was by the ancient Greek scholar Theophrastus, student of Plato and Aristotle and successor to the latter. On 17 March AD 807 Benedictine monk Adelmus observed a large sunspot that was visible for eight days; however, Adelmus incorrectly concluded he was observing a transit of Mercury. The earliest surviving record of deliberate sunspot observation dates from 364 BC, based on comments by Chinese astronomer Gan De in a star catalogue. By 28 BC, Chinese astronomers were regularly recording sunspot observations in official imperial records. A large sunspot was observed at the time of Charlemagne's death in AD 813. Sunspot activity in 1129 was described by John of Worcester and Averroes provided a description of sunspots later in the 12th century; however, these observations were also misinterpreted as planetary transits. The first unambiguous mention of the solar corona was by Leo Diaconus, a Byzantine historian. He wrote of the 22 December 968 total eclipse, which he experienced in Constantinople (modern-day Istanbul, Turkey): The earliest known record of a sunspot drawing was in 1128, by John of Worcester.