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Some questions on obtaining solar observing data

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#1 Alan S

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Posted 24 October 2021 - 12:03 PM

As I work on a return to regular sketching, I am curious about resources for a few things-

 

First, is there a website that provides the current Carrington rotation #?  The closest I found shows the past start/stop times for rotations and is this: http://umtof.umd.edu/pm/crn/

Obviously this implies when the current rotation started, but does not specify when it will end (yes, I could estimate).  I used to have a site I could look at whenever I made a sketch that had the current information.

 

Second, as far as sunspot number, I know I can look at Spaceweather.com and see a sunspot number in the left hand column.  I am curious, however, what site(s) others use.  This question arises for me as I was trying to look at historic daily numbers to add back to some of my sketches from the past (I have many), I discovered that there are inconsistencies in the historic daily numbers - perhaps from individual observers calculating them, perhaps for being recorded at different times within a day...or who knows what else.

 

This leads me to another question - is there a time when the daily number is recorded/official?  In other words, 0000 UTC each day, or maybe 1200, or when an observer at NOAA comes back from the first coffee break lol.gif ?  It would seem that it should be done at the same time each day...

 

Best,

Alan


Edited by Alan S, 24 October 2021 - 12:06 PM.


#2 Alan S

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Posted 24 October 2021 - 10:48 PM

60 plus views and no suggestions…anyone?

cricket.gif



#3 peterm

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Posted 25 October 2021 - 12:19 AM

Not sure if this site helps but at the bottom it notes this re: historical data.

 

https://www.swpc.noa...ar-synoptic-map

 

"Synoptic maps of the solar surface are drawn each day by SWPC forecasters, providing forecasters with a broad outline of solar surface features. These maps were started on June 2, 1972 and have been produced daily since then. They show neutral lines, coronal hole boundaries, active regions, plages, filaments and prominences. The maps also have information about coronal hole polarity, list active region numbers, and have flare and proton event probabilities for each region. The historical synoptic maps are available at NGDC."

 

https://www.ngdc.noa...awings/boulder/

 

And this below from this site: So, two observatories... never knew that, so I have learnt something valuable from your question, thank you!  Probably rules out the coffee break unless they synchronise the coffee pot!

https://hesperia.gsf....htm#AR_numbers

 

 

"There is no naming or numbering system for sunspots. There is a system for numbering active regions, however. An active region can contain one or more spots. The National Oceanic and Atmospheric Administration (NOAA) numbers active regions consecutively as they are observed on the Sun. According to David Speich at NOAA, an active region must be observed by two observatories before it is given a number (a region may be numbered before its presence is confirmed by another observatory if a flare is observed to occur in it, however). The present numbering system started on January 5, 1972, and has been consecutive since then. An example of an active region "name" is "AR5128" (AR for Active Region) or "NOAA Region 5128". Since we only see active regions when they are on the side of the Sun facing the Earth, and the Sun rotates approximately once every 27 days (the equator rotates faster than the poles), the same active region may be seen more than once (if it lasts long enough). In this case the region will be given a new number. Hence, a long-lived active region may get several numbers."


Edited by peterm, 25 October 2021 - 12:30 AM.

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#4 Alan S

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Posted 25 October 2021 - 10:09 AM

Thanks- that is interesting information for sure.

 

I am still curious as to the timing of the daily sunspot #, and who determines that.  Is it NOAA SPWC alone, or a similar 2 observatory requirement...???

 

I enjoy visiting the daily sunspot drawing made at the 150 ft. Solar tower at Mt. Wilson, as they also have a long record of daily observations...since 1917!

http://obs.astro.ucla.edu/cur_drw.html



#5 dhkaiser

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Posted 25 October 2021 - 11:06 AM

https://spaceweather...spotnumber.html



#6 Alan S

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Posted 25 October 2021 - 11:59 AM

Thanks!  That explains a lot about some of the inconsistencies in historic numbers I was finding for specific dates.

 

I find it interesting that there are (in 2021!) two 'official' sunspot numbers in use with the Boulder (calculated by NOAA) being ~25% higher than the 'International sunspot number' (calculated by the Solar Influences Data Center in Belgium)...and while they use the same basic formula for calculating, the difference is due to the raw data being from different observatories!!

 

I am surprised that with the technology we have now (including satellites monitoring the far side of the Sun), that the international community has not standardized the calculation of the daily sunspot number.

 

Maybe we should create a daily Cloudy Nights Sunspot number using the data from all the observers reporting on CN rofl2.gif 




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