Sunspot drawing or sunspot sketching is the act of drawing sunspots. Sunspots are darker spots on the Sun's photosphere. Their prediction is very important for radio communication because they are strongly associated with solar activity which can seriously damage radio equipment.
Sunspots were probably first drawn by an English monk John of Worcester in 8th December 1128. There are records of observing sunspots from 28 BC but this is the first drawing of sunspots, almost 500 years before the telescope. His drawing seems to come around solar maximum. Five days later, the Korean astronomer saw the northern lights above his country, so this is also the first prediction of coronal mass ejection
In 1612, Galileo Galilei was writing letters on sunspots to Mark Welser. They were published in 1613. In his telescope, he saw some darker spots on Sun's surface. It seems like he was observing the Sun and drawing sunspots without any filter which is very hard. From there it seems that he observed the Sun at sunset, but not at sunrise because of the high horizon of Apennines. It is also possible, that he was referring to Scheiner's observation, where he first saw that the Sun is rotating. He was complaining, that he couldn't observe the Sun every morning and evening because of low clouds and so he couldn't see their motion with confidence. Probably he never observed in the middle of the day. In the same year, his student Benedetto Castelli invented a new method for observing and drawing sunspots, the projection method. Probably he was never looking at the Sun directly through the telescope.
Mount Wilson observatory started drawing sunspots by hand in 1917. This tradition continues still today. The early drawers weren't drawing their shapes and position very accurate because they wanted just to mark where the sunspots were on the magnetic data. But in modern times, the drawers became very accurate, this became art; sometimes they needed many hours to complete work. On the white acid-free paper, they draw a circle with solar coordinates. They draw and mark sunspots. Then the date and the seeing are written.
In the media
- Fox, Karen C. "Impacts of Strong Solar Flares". NASA. Retrieved 24 July 2020.
- Peplow, Mark. "John of Worcester spot on with his 1128 sun diagram". The Telegraph. Retrieved 24 July 2020.
- Young, Andrew T. "Galileo's sunspot letters to Mark Welser". Retrieved 26 July 2020.
- "Galileo's sunspot letters". British Library. Retrieved 26 July 2020.
- Webster, Larry. "The 150-Foot Solar Tower Sunspot Drawing". Mount Wilson Observatory. Retrieved 26 July 2020.
- Historical Sunspot Drawing Resource Page
- Mt. Wilson 150-Foot Solar Tower Current Sunspot Drawing
- Sunspots - Stanford Solar Center
- Sketching Sunspots - Sky & Telescope - Sky & Telescope
- The earliest drawing of sunspots - Oxford Academic Journals
- Galileo's Sunspot Drawings - The Galileo Project
- A drawing of observed sunspots - SIDC
- Sunspot drawings at Kodaikanal Observatory: a ... - SpringerLink
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