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AR2201 in white light?

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davidjayjackson
davidjayjackson's picture
AR2201 in white light?

Greeting,

Meade ETX 125 +30mm(x63) EP.; 1000 Oaks film filter

Spaceweather.com show a solar feature labeled AR2201 (right side)

But I am unable to see anything (no spot or discolaration) at that location?

Is is just not visable in white light?

 

Thanks,

David

HRHA
HRHA's picture
white light vs Boulder active regions

 Hi David,

Spaceweather.com uses the Boulder group designation for the Active Regions.  These AR numbers come from the Boulder observatory, and the USAF ISOON observatories and a few others scattered around the world. They are made up of H -alpha and Ca II spectral lines.  So there will be AR numbers for groups that you wont see with a white light filter. They may evolve into visible groups and sunspots, but not always.  Only record what you can see thinking in the Zurich classification scheme.  

Rodney

attached is a short description of the Boulder method

davidjayjackson
davidjayjackson's picture
Rodney,  Thanks for

Rodney, 

Thanks for that. 

What is a  reliable source for the daily wolf number?

 

David

 

ASA
ASA's picture
daily wolf number

Hi David.

 

a  reliable source for the daily wolf number?

 

here: SILSO.

http://sidc.oma.be/silso/

Salvador.

 

 

davidjayjackson
davidjayjackson's picture
Salvador,  Thanks for that

Salvador, 

Thanks for that link.

I was relieved to see my numbers are in the ball park :)

David

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