<p>How a sunspot number is calculated by an individual observer?</p>
<p>I would like to learn how to calculate the daily number of sunspots and where to get daily input images of the Sun.</p>
<p>I have read tens of web links and none mentioned or described any algorithm to work for the calculation of the sunspot number.</p>
<p><a href="https://analyzer.depaul.edu/paperplate/Tracking%20Sunspots.htm" rel="nofollow noreferrer">https://analyzer.depaul.edu/paperplate/Tracking%20Sunspots.htm</a></p>
<p>What is the number of sunspots in this paper plate drawing?</p>
<p><a href="https://analyzer.depaul.edu/paperplate/images/Sun_trace_Clyde_zoomR.jpg" rel="nofollow noreferrer">https://analyzer.depaul.edu/paperplate/images/Sun_trace_Clyde_zoomR.jpg</a></p>
<p>visited NOAA, NASA, ESA, SILSO</p>
<p><a href="https://www.sidc.be/silso/dayssnplot" rel="nofollow noreferrer">https://www.sidc.be/silso/dayssnplot</a></p>
<p>and still no hint and how numbering, encoding is assigned to individual sunspots in the paper plate drawing  (as above).</p>

CC BY-SA 4.0
2022-11-01T22:51:03.397Z
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
CC BY-SA 4.0
2022-11-01T23:02:10.627Z
@LifeInTheTrees since  s is the number of spots, so how do you calculate that number ?
Exactly what I was asking about.
darius
CC BY-SA 4.0
2022-11-02T00:22:10.067Z
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
CC BY-SA 4.0
2022-11-02T07:00:14.030Z
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
CC BY-SA 4.0
2022-11-02T07:06:03.620Z
Here is a moment where a lady gives a pretty good run thru and an example: https://youtu.be/aeYM3WVCxc8?t=993
bandybabboon
CC BY-SA 4.0
2022-11-02T13:15:57.563Z
@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
CC BY-SA 4.0
2022-11-02T13:50:30.233Z
@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
CC BY-SA 4.0
2022-11-02T22:09:13.557Z
@PierrePaquette  counting quickly numbers of sunspots above the W-E line I get 56 sunspots vs. your count of 35.
darius
CC BY-SA 4.0
2022-11-02T23:35:18.847Z
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
CC BY-SA 4.0
2022-11-03T00:41:38.113Z
@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
CC BY-SA 4.0
2022-11-03T11:11:48.087Z
@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
CC BY-SA 4.0
2022-11-03T13:38:53.717Z
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
CC BY-SA 4.0
2022-11-03T19:27:04.680Z
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
CC BY-SA 4.0
2022-11-03T21:43:23.770Z
@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

29. The STARA Sunspot Catalog


Fraser Watson
National Solar Observatory, Tucson, AZ 85719, USA
darius
CC BY-SA 4.0
2022-11-03T21:56:05.383Z
2. 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
CC BY-SA 4.0
2022-11-04T05:00:49.570Z
@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
CC BY-SA 4.0
2022-11-04T11:37:03.623Z
@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
CC BY-SA 4.0
2022-11-04T19:13:47.537Z
@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
CC BY-SA 4.0
2022-11-04T20:59:53.567Z
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
CC BY-SA 4.0
2022-11-05T16:17:02.430Z
@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
CC BY-SA 4.0
2022-11-05T22:40:28.540Z
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.sstatic.net/71vvu.jpg
Tony Stewart EE75
CC BY-SA 4.0
2022-11-06T15:47:52.450Z
@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
CC BY-SA 4.0
2022-11-07T09:42:06.170Z
"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
CC BY-SA 4.0
2022-11-09T00:17:44.417Z
"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
CC BY-SA 4.0
2022-11-09T00:19:51.777Z
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
CC BY-SA 4.0
2022-11-09T00:40:20.250Z
https://www.bing.com/images/search?q=sunspots+high+resolution+%5c&qpvt=sunspots+high+resolution+%5c&form=IGRE&first=1&tsc=ImageHoverTitle
darius
CC BY-SA 4.0
2022-11-10T23:50:42.103Z
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
CC BY-SA 4.0
2022-11-13T02:24:39.467Z
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
CC BY-SA 4.0
2022-11-16T18:40:19.057Z
@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
<sunspots>
How a sunspot number is calculated by an individual observer?
darius
# How a sunspot number is calculated by an individual observer?

(Asked by: username_0 on 2022-11-01)

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).

**Tags:** sunspots

> **Comments:**
> **username_1**: 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?  
> **username_0**: @LifeInTheTrees since  s is the number of spots, so how do you calculate that number ? Exactly what I was asking about.  
> **username_2**: 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.”  
> **username_1**: 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  
> **username_1**: Here is a moment where a lady gives a pretty good run thru and an example: https://youtu.be/aeYM3WVCxc8?t=993  
> **username_0**: @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 ?  
> **username_0**: @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.  
> **username_0**: @username_2  counting quickly numbers of sunspots above the W-E line I get 56 sunspots vs. your count of 35.  
> **username_0**: 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  
> **username_2**: @username_0 As I said it’s difficult to know which one is a single spot and which one is a double or triple sunspot…  
> **username_0**: @username_2 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  
> **username_0**: 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/  
> **username_1**: 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.  
> **username_0**: @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  29. The STARA Sunspot Catalog   Fraser Watson National Solar Observatory, Tucson, AZ 85719, USA  
> **username_0**: 2. 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  
> **username_2**: @username_0 On the image you link to, it’s difficult to count the spots. On the actual Sun, I agree, it’s not difficult.  
> **username_0**: @username_2  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 ?  
> **username_0**: @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  
> **username_1**: 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.  
> **username_0**: @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  
> **username_3**: 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.sstatic.net/71vvu.jpg  
> **username_0**: @username_3  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  
> **username_0**: "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  
> **username_0**: "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)  
> **username_0**: 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.  
> **username_0**: https://www.bing.com/images/search?q=sunspots+high+resolution+%5c&qpvt=sunspots+high+resolution+%5c&form=IGRE&first=1&tsc=ImageHoverTitle  
> **username_0**: 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  
> **username_3**: 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  
> **username_0**: @username_3 sorry  Stewart username_3, 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  

---

## 0 answers

