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How a sunspot number is calculated by an individual observer?

I would like to learn how to calculate the daily number of sunspots and where to get daily input images of the Sun.

I have read tens of web links and none mentioned or described any algorithm to work for the calculation of the sunspot number.

https://analyzer.depaul.edu/paperplate/Tracking%20Sunspots.htm

What is the number of sunspots in this paper plate drawing?

https://analyzer.depaul.edu/paperplate/images/Sun_trace_Clyde_zoomR.jpg

visited NOAA, NASA, ESA, SILSO

https://www.sidc.be/silso/dayssnplot

and still no hint and how numbering, encoding is assigned to individual sunspots in the paper plate drawing (as above).

Fred
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darius
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    Isnt there a guide for the formula.. k(10 g + s) where g is the number of sunspot regions, s is the number of spots, and k is a variable quantifying observing conditions and observer biases? – bandybabboon Nov 01 '22 at 22:51
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    @LifeInTheTrees since s is the number of spots, so how do you calculate that number ? Exactly what I was asking about. – darius Nov 01 '22 at 23:02
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    As far as I know, it’s the number of spots. The same thing as, e.g., the number of slices of pepper on a pizza. I count ≈ 35 in the drawing you link to, although it’s sometimes difficult to distinguish between two spots or a single large one that is “wasp-shaped.” – Pierre Paquette Nov 02 '22 at 00:22
  • Try this https://www.google.com/search?q=how+to+count+sunspots&client=ms-unknown&prmd=ivsn&sxsrf=ALiCzsaVuEfZhYkTMm7Xiys3fYi2KooJTw:1667372263597&source=lnms&tbm=vid&sa=X&ved=2ahUKEwjgj-vb9Y77AhUQSxoKHfLoBboQ_AUoAnoECAIQAg&biw=384&bih=679&dpr=2.81 – bandybabboon Nov 02 '22 at 07:00
  • Here is a moment where a lady gives a pretty good run thru and an example: https://youtu.be/aeYM3WVCxc8?t=993 – bandybabboon Nov 02 '22 at 07:06
  • @LifeInTheTrees

    thank you exactly what I mean

     https://youtu.be/aeYM3WVCxc8?t=1942

    watch this still image taken from the video and tell me why the number of sunspots jumps from 6 to 16 for the same blurred image

    Ok, I can detect 7 sunspots but how could I count 16 sunspots ?

     – darius Nov 02 '22 at 13:15
  • @LifeInTheTrees do you mean the following paper plate drawing ? --

    https://analyzer.depaul.edu/paperplate/images/Sun_trace_Clyde_zoomR.jpg

    __ I watched carefully the encoding assigned and attached to individual groups of sunspots and discovered the encoding system: Eai13 stays for 13 sunspots, Fhi11 stays for 11 sunspots, Axx1 stays for 1 sunspot, ... . So counting quickly the numbers of sunspots above the W-E line I get 56 sunspots vs. your count of 35. Since image is blurred for small sunspots the only reliable to me sunspots count is encoded as Axx1.

     – darius Nov 02 '22 at 13:50
  • @PierrePaquette counting quickly numbers of sunspots above the W-E line I get 56 sunspots vs. your count of 35. – darius Nov 02 '22 at 22:09
  • Sunspot Surface Calculation Case Study Project

    unfortunately, never completed

    https://www.codeproject.com/Articles/812896/Sunspot-Surface-Calculation-Case-Study-on-solving?msg=5907254#xx5907254xx

     – darius Nov 02 '22 at 23:35
  • @darius As I said it’s difficult to know which one is a single spot and which one is a double or triple sunspot… – Pierre Paquette Nov 03 '22 at 00:41
  • @PierrePaquette nothing is hard, since number of sunspots is counted daily by 100+ sites

    visit of the coordinators from Japan and count the number of sunspots from the solar image attached below the charts vs. 75 counted by them https://swc.nict.go.jp/en/trend/sunspot.html

     – darius Nov 03 '22 at 11:11
  • Tried to contact Chuck Bueter from Paper Plate Sunspots Project

    but his mail server is down Address not found Your message wasn't delivered to bueter@transitofvenus.org because the address couldn't be found or is unable to receive email.

    https://analyzer.depaul.edu/paperplate/images/Sun_trace_Clyde_zoomR.jpg from Linkedin Independent Informal Education Professional

    Granger, Indiana, United States Contact info

    https://analyzer.depaul.edu/paperplate/

     – darius Nov 03 '22 at 13:38
  • Yes it's something that should be easy to measure algorythmically these days, for example, just getting the total surface area that is dark and the number of different regions is really easy for today's image processing maths. Then everyone could just pass images of the sun through a standardized advanced analysis equation and it would be more accurate and systematic than manual counting, including resolution k values surmised by pixel count and that kind of factor. – bandybabboon Nov 03 '22 at 19:27
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    @LifeInTheTrees you are right and I am ready to start with morphological analysis of sunspots. In the mean time I have visited 100+ websites

    STARA Project: STARA

    https://theses.gla.ac.uk/3429/1/2012watsonphd.pdf

    Glasgow Theses Service http://theses.gla.ac.uk/ theses@gla.ac.uk Watson, Fraser Thomas (2012) Investigating sunspot and photospheric magnetic field properties using automated solar feature detection. PhD thesis. http://theses.gla.ac.uk/3429

    1. The STARA Sunspot Catalog

    Fraser Watson National Solar Observatory, Tucson, AZ 85719, USA

     – darius Nov 03 '22 at 21:43
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  • Sunspot Surface Calculation (Case Study on solving complex problems)

    • V.

    https://www.codeproject.com/Articles/812896/Sunspot-Surface-Calculation-Case-Study-on-solving?msg=5907254#xx5907254xx

    abandoned project since V. left institute I need to contact Chuck Bueter from Paper Plate Backyard Astronomy Project analyzer.depaul.edu/paperplate since his sunspots count is for real

    analyzer.depaul.edu/paperplate/images/Sun_trace_Clyde_zoomR.jpg

    He moved from project to project and hope to contact him via Facebook one day. Than I go to Japan: swc.nict.go.jp/en/trend/sunspot.html

    – darius Nov 03 '22 at 21:56
  • @darius On the image you link to, it’s difficult to count the spots. On the actual Sun, I agree, it’s not difficult. – Pierre Paquette Nov 04 '22 at 05:00
  • @PierrePaquette you are right, naked eye backyard telescope sunspot observations are great. But NASA, NOAA, ESA and 10+ agencies use prerecorded images for postprocessing.

    from https://spaceweather.com/

    2M labeled sunspots https://spaceweather.com/images2022/03nov22/hmi1898.gif

    4M no labels sunspots https://spaceweather.com/images2022/03nov22/hmi4096_blank.jpg

    Sunspot number: 65 4M is clear, sharp Sunspot number: 65

    3135 label - 2 sunspots/ groups 3136 label - 2 sunspots/ groups

    R = K (10g + s) = 65 ? what is a number of groups in the image ?

     – darius Nov 04 '22 at 11:37
  • @LifeInTheTrees

    "getting the total surface area that is dark and the number of different regions is really easy for today's image processing maths.

    https://swc.nict.go.jp/data/latest/sdo/latest_512_HMIIF.mp4

    Total surface area is not easy sunspots index if sunspots look like tiny pixels in the video above

    So sunspots count still matters

     – darius Nov 04 '22 at 19:13
  • yes its easy to include that. I specialize in image processing... Its really easy to count any kind of edges and distances from any spots. Equator alignment, groups, total surface area, far more with computers. – bandybabboon Nov 04 '22 at 20:59
  • @LifeInTheTrees ok, go on with image processing

    There is another guy interested in total surface of sunspots

    Gimp supports supports back projection of 2D solar disc image onto sphere

    https://groups.google.com/g/uk.sci.astronomy/c/7IbJzwTF2fQ

    Hope to get script to count black pixels on the sphere

    Tried Mosaic and more tools for morphological image analysis

    But need to learn working definition of the group of sunpots as defined in astronomy

     – darius Nov 05 '22 at 16:17
  • I don't see yet how they define a sunspot on the 4Meg image. I can enhance it to find a lot more than 65. But pixel counting is easy. Choosing the threshold is hard.. https://i.stack.imgur.com/71vvu.jpg – Tony Stewart EE75 Nov 05 '22 at 22:40
  • @TonyStewartEE75 your image file is 1M 71vvu.jpg (image JPEG, 937×843 pixels)

    sunspot/s in the image is/are called a groups of sunspots one day and individual sunspots another day

    Since number of sunspots index is published officially every day all I need is to verift the published count against input image file at preset resolution.

    What input image resolution is set for the official count of sunspots in Japan, US, Greenwich, Belgium?

    I assume naked eye observations of solar disc are not done real time for sunspot count https://solarscience.msfc.nasa.gov/greenwch.shtml

     – darius Nov 06 '22 at 15:47
  • "under a po\ver which presented a picture of about I I inches diameter

    Is 11 inches diameter a standard in naked eye or camera observations ?

    https://watermark.silverchair.com/mnras20-0013.pdf

    4tt:r. Carrington, Singular Appe~rance in the Sun

    Description of a Singular Appearance seen in tlte Sun on September 1, I 859· By R. C. Carrington, Esq

    The image of the sun's disk was, as usual '\Vith me, projected on to a plate of glass coated with distemp~r of a pale straw colour, and at a distance and under a po\ver which presented a picture of about I I inches diameter

     – darius Nov 07 '22 at 09:42
  • "The Sun in high resolution 24/03/2022

    The Sun as seen by Solar Orbiter in extreme ultraviolet light from a distance of roughly 75 million kilometres. The image is a mosaic of 25 individual images taken on 7 March by the high resolution telescope of the Extreme Ultraviolet Imager (EUI) instrument. In total, the final image contains more than 83 million pixels in a 9148 x 9112 pixel grid, making it the highest resolution image of the Sun’s full disc and outer atmosphere, the corona, ever taken.

    ESA & NASA/Solar Orbiter/EUI team; Data processing: E. Kraaikamp (ROB)

     – darius Nov 09 '22 at 00:17
  • https://www.esa.int/ESA_Multimedia/Images/2022/03/The_Sun_in_high_resolution

    https://www.esa.int/var/esa/storage/images/esa_multimedia/images/2022/03/the_sun_in_high_resolution/24010613-1-eng-GB/The_Sun_in_high_resolution.jpg

    In total, the final image contains more than 83 million pixels in a 9148 x 9112 pixel grid, making it the highest resolution image of the Sun’s full disc and outer atmosphere, the corona, ever taken.

     – darius Nov 09 '22 at 00:19
  • https://www.bing.com/images/search?q=sunspots+high+resolution+%5c&qpvt=sunspots+high+resolution+%5c&form=IGRE&first=1&tsc=ImageHoverTitle – darius Nov 09 '22 at 00:40
  • Number of sunspots counted manually (raw data): 34 -- Updated 10 Nov 2022

    Image 1 - 2M https://spaceweather.com/images2022/10nov22/hmi1898.gif

    Image 2 - 4M https://spaceweather.com/images2022/10nov22/hmi4096_blank.jpg

    Image 3 https://www.sidc.be/uset/data/cameras/output_img/png/L1c_png_2048_text/USET_White_Light/2022/11/UPH20221110131943.png

    Image 4 https://swc.nict.go.jp/data/latest/sdo/latest_512_HMIIF.jpg?20220404

     – darius Nov 10 '22 at 23:50
  • Pixels have a dynamic range in bits and a SNR in dB with a spectral density filter in nm. Heat is easily spotted in Red waves near 660nm but CME is easier seen in XRays and UV. Find out the algorithm. Don't guess. This imager has an EUI range but your images are red only wavelength colorized https://scied.ucar.edu/interactive/sun-compare-multispectral , https://www.sidc.be/sunspots/bulletins/monthly/monthlybull202210.pdf – Tony Stewart EE75 Nov 13 '22 at 02:24
  • @TonyStewartEE75 sorry Stewart EE75, but images of solar disc by SIDS.be are of low quality, low resolution, blurred, so not fit for manual count of sunspots

    https://www.sidc.be/uset/data/cameras/output_img/png/L1c_png_2048_text/USET_White_Light/2022/11/UPH20221110131943.png

    As NASA Citizen Scientist I hope to get quality images of solar disc, acquired by @ NASA

     – darius Nov 16 '22 at 18:40