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Hi Stephen, Question. How was it that I could see four small sun spots yesterday, the active region is still active today but without any spots visible today?

Thanks Buddy

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An AR can be 'spotless'...Someone with more technical know how will have to explain why some do and don't...

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Blue skies,
Stephen "Darkstar" Ames
PST(#96038), VIXEN 8-24mm,CEMAX 2x Barlow, Thousand Oaks White Light Filter and a Meade Elec EP
CFI, CFII, MEI, working on EIEIO!
BAA Member
My solar site:

http://seemysunspot.com

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Hi Stephen, Question. How was it that I could see four small sun spots yesterday, the active region is still active today but without any spots visible today?

Thanks Buddy

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Yes, an active region can indeed not contain any sunspots. In H-alpha, one of these spotless regions will show some plage and perhaps a few small fibrils or filaments. One of the largest and longest-lived solar flares I have ever seen happened in a spotless active region (a filament "Long Duration Event"). Sunspots can fade away in only a day as their magnetic field strength decays, so it is fairly common to see at least small ones seem to vanish overnight. Clear skies to you.

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David W. Knisely
Hyde Memorial Observatory
http://www.hydeobservatory.info
Prairie Astronomy Club
http://www.prairieastronomyclub.org

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How was it that I could see four small sun spots yesterday, the active region is still active today but without any spots visible today?

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I got a very brief sunny interval between the front clearing and the first shower rolling in - I was unable to complete my normal round of observations but did see the spot in white light, it was quite small though and could easily have been overlooked. There was a tiny pore immediately following it.

I failed to image the spots and could not observe at all in Ha due to the cloud. The only image I managed to capture today was the whole disk CaK shot, which does just about show the spot (at the right hand end of the tick-shaped bright plage).


2009 Nov 06, 1314 UT. PST CaK at prime focus. Transparency fair, seeing poor.

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