*Question by Jeff Engr*: How are Sun Spot numbers being calculated?

How are they calculating the sun spot numbers? I asked this in another seciton on this forum and am getting no serious answers. I placing same question here as I value many of the opinions on this section even those I disagree with… Please only reasonable answers, this is an honest scientific curiosity for me.

i.e.

For May 2 there was one sun spot #1203 and the sunspot number was 57

For May 3 there are 4 sun spots #1200, 1203, 1204, and 1205 but the sunspot number is 51

The equation they give is R=k (10g+s)

where R is the sunspot number; g is the number of sunspot groups on the solar disk; s is the total number of individual spots in all the groups; and k is a variable scaling factor (usually <1) that accounts for observing conditions and the type of telescope (binoculars, space telescopes, etc.). Scientists combine data from lots of observatories -- each with its own k factor -- to arrive at a daily value.
so unless k varies VERY widely, the sunspot numbers they are giving us appear to be bunk.
Please help. How large can k get? during the deep solar minimum k was almost never less than 1...
The equation comes from the website http://www.spaceweather.com/ which is run by Dr. Tony Phillips I think from NASA but I'm not sure on that...
I am honestly looking for a reasonable explanation from someone who has at least a minimal level of scientific training. I am asking because I thought I understood how it is done, but based on # of sunspot groups and total number of spots, the only explanation I can find for the widely varying sunspot values is due to a widely varying value for the variable k. Given that, I really want to know how a value for k is determined.
Saying scientists do it is good for grade school children, but not for those of us who know mathematics physics etc and have legitimate questions. for k to have true scientific value then how a value for k is determined is HIGHLY relevant and should be determined based on a set algorithm. I'd like to better understand that algorithm...
**Best answer:**

*Answer by Peter J*

This answers it very clearly…

http://spaceweather.com/glossary/sunspotnumber.html

This explains the “K” factor

http://sidc.oma.be/news/106/sunspotnumberclarified.pdf

The K factor is more sensibly calculated than trusting a single thermometer in the arctic to tell us the average temperature of thousands of square miles of arctic.

**What do you think? Answer below!**

Comments are closed.