Royal Observatory vs. SpaceWeather.com Wolf number: 159 vs. 117 (09 Jan 2023) what's wrong ?

Affiliation
American Association of Variable Star Observers (AAVSO)
Tue, 01/10/2023 - 16:14

Royal Obserwatory of Belgium

6 groups
99 sunspots
Wolf number: 159

https://www.sidc.be/uset/data/drawings/2023/01/usd202301091326.jpg

SpaceWeather.com

Wolf number: 117

Dated 09 Jan 2023

Affiliation
American Association of Variable Star Observers (AAVSO)
There is nothing "wrong" except you are comparing apples...

... to oranges. This is why you cannot take the Spaceweather counts as "gospel" for doing AAVSO solar observing. We have said here in other posts that you will NOT normally get the same sunspot number that is published on that website. Magnetic group counts are different from morphologically and evolutionarily determined groups, and solar astronomers have carefully looked into how the various observers' records can be aggregated into a scientific useful record. We need to be able to compare our data today with that going back to Galileo (and before in some cases) in order to reconstruct the solar cycle record, which means we cannot rely on magnetically determined groups. Galileo didn't have a magnetometer. Please read section 4 of the following paper: https://link.springer.com/content/pdf/10.1007/s11207-015-0815-8.pdf  .

As Rodney and I have both said previously, the best way to get into solar observing is to simply do it, make your best estimates of groups and careful counting of spots, following the rules set out in the AAVSO solar observing guide and taking into account the common morphologies of sunspot groups and their evolution, and then going back each month and comparing your R to the raw R values listed in the Solar Bulletin to see how your numbers compare to the averages of the other observers. Spaceweather can be used to alert you to the overall activity, but remember that this is a snapshot in time - when YOU look at the sun, some groups will have rotated out of view, others will have rotated into view, some will have died and others will be born. Also note that unless you have a magnetometer on your face instead of eyeballs, you will be identifying groups morphologically, and therefore will not get the same answer that you will see on Spaceweather.  

KL

Affiliation
American Association of Variable Star Observers (AAVSO)
Thank you, but I need to…

Thank you, but I need to limit my spending

- 39,95 € for PDF version -

so I prefer Google Scholar references like

https://adsabs.harvard.edu/pdf/1861MiZur...2...41W

 

Ok, Spaceweather publishes images of solar disc by NOAA/NASA but the original images are time stamped, so rotation can be read from another video animation by NASA.

Since images by NASA are time stamped and fixed they are fit as a public vision test among sun observers.

My present interest is in pro observers of the sun to verify if the pro observers can count the same number of visible sunspots on a daily basis

and if not, why not.

 

I am afraid, the Group Sunspot Number can be soon replace Wolf number, abolishing the need for counting the indiviual sunspots.

Groups can be computer generated from magnetograms, identified as active regions AR, turned groups.

------------------------------------

https://link.springer.com/article/10.1023/A:1005056326158

Group Sunspot Numbers: A New Solar Activity Reconstruction

Solar Physics volume 181page 491 (1998)Cite this article

Abstract

In this paper, we construct a time series known as the Group Sunspot Number. The Group Sunspot Number is designed to be more internally self-consistent (i.e., less dependent upon seeing the tiniest spots) and less noisy than the Wolf Sunspot Number. It uses the number of sunspot groups observed, rather than groups and individual sunspots.

----

 

 

 

References

Hi Darius,

Thank you for looking into these references. There is a group number data file here, https://www.sidc.be/silso/groupnumberv3

with most of the observes (stations) going back to 1610. Look at the draft report.  Perhaps it will help understand how observers all over the world have different seeing conditions under the clouds. 

Rodney

 

Affiliation
American Association of Variable Star Observers (AAVSO)
Thank you.Tried to chart…

Thank you.

Tried to chart the above file in the cloud but it fails due to bugs in input data.

 

YEAR MONTH DAY STATION OBSER GROUPS

2010 11 27 570 1 1 2010 11 27 572 1 3 2010 11 27 577 1 2 2010 11 27 589 1 0 2010 11 27 595 1 1 2010 11 27 597 1 1 2010 11 27 606 1 2 2010 11 27 613 1 2 2010 11 27 615 1 1 2010 11 27 616 1 1 2010 11 27 620 1 0 2010 11 27 622 1 1 2010 11 27 630 1 1 2010 11 27 633 1 1 2010 11 27 639 1 2 2010 11 27 646 1 2 2010 11 27 664 1 2 2010 11 27 677 1 1 2010 11 27 685 1 0 2010 11 27 688 1 1 2010 11 27 701 1 2 2010 11 27 708 1 2 2010 11 27 713 1 1 2010 11 27 714 1 1

sorry C&P formatting not supported, but believe me or not, the above data records represent a single day: 2010 11 27

Frederic from SILSO not responding

I still hope to get from SILSO raw numbers of sunspots as counted by observers, representing the past

 

---

follow-up

Modern data, representing the recent past : 2010 11 27

and

Station number:  recorded number of groups:

570:  1

572:  3

589:  0

606:  2

 

not meeting data quality standards in metrology