On-line Vision Test for sun watchers, sketching sunspots

American Association of Variable Star Observers (AAVSO)
Mon, 12/26/2022 - 20:58

first by @Essilor



and the second, as count of sunpots from images of solar disc


AI #Sunspots Count Vision Test from Santa




Let me know your opinion if sun watchers should take such on-line vision tests from time to time




American Association of Variable Star Observers (AAVSO)

It is always a good idea to keep your eye prescription up to date (if you wear glasses or contacts). It is important for telescope viewing that you try to maximize your seeing conditions and make sure your telescope is well-focused. Your calculated K factor should take care of any consistent minor issues, as long as you do your part to observe as carefully as you can. 


In the two pictures you posted, there are 2 active areas with group numbers that you would probably not see when observing (no dark umbras visible) so your Wolf number would be lower than what you might see on the Spaceweather website, and that is ok. The important thing is to observe consistently and carefully, reporting what YOU see with YOUR equipment. 

When I was starting out, I really learned best by going back the next month after the Solar Bulletin came out and checking my logbook against the RAW average numbers for each date. If my numbers were too high (by 10 or more) I was probably subdividing groups (something I did a lot when I was starting out). You can fix this with practice by learning what a group looks like and looking at the Solar Observing Guide sketches of the evolution of groups. If I was too low (by 10 or more), I was usually missing groups (probably along the limb) or a faint one at the limit of visibility. You can fix this by always carefully checking the east and west edges of the sun. Remember that if there are problems with your observing conditions (such as the limb of hte sun being turbulent) you should add this to the comment column of Sun Entry.

Thanks for being so eager to be a great observer! It comes with time and practice, and yes, even seasoned observers make mistakes sometimes. 


- Kris Larsen

American Association of Variable Star Observers (AAVSO)
Thank you very much for…

Thank you very much for your kind comments and remarks.


Just reading


Rudolf Wolf - Sunspot observations in the second half of the year 1849


Tried to contact David Speich at NOAA to learn more about how Active Regions are computer generated

but he is not living on social media

and the link below is down


and forum at BritAstro is not active to get the right link.


I plan to read books, papers, articles by Rudolf Wolf to learn how the idea of the Wolf number originated

since no mention of Wolf number in 1849.


Was it him, who started to count sunspots that way or the formula was developed by someone else and named after Wolf only.


Wikipedia search for Wolf number gives no clear answer.



I am afraid, computer-based  processing of images of solar disc may generate one day Zero-Sunspot Active Region. since batch processing is not human controlled.



thank you once again for your time

and wish you Happy New Year 2023




I am lost if I open many pages in web browser and try to find one opened a week ago.

There must be some tools to make web history turned into a single page made of small png images of opened web pages.


Otherwise I am lost and my learning curve remains flat